diff --git a/crates/xserial-client/src/config.rs b/crates/xserial-client/src/config.rs
index b007145..3872156 100644
--- a/crates/xserial-client/src/config.rs
+++ b/crates/xserial-client/src/config.rs
@@ -5,10 +5,12 @@ use xserial_core::frame::{
     fixed::FixedLengthFramer,
     length::{LengthConfig, LengthPrefixedFramer},
     line::{LineConfig, LineFramer},
+    mixed::{MixedTextPlotConfig as MixedFramerConfig, MixedTextPlotFramer},
 };
 use xserial_core::protocol::{
     ProtocolDecoder,
     hex::{HexConfig, HexDecoder},
+    mixed::{MixedTextPlotConfig as MixedDecoderConfig, MixedTextPlotDecoder},
     plot::{PlotConfig, PlotDecoder, PlotFormat, SampleType},
     text::{TextDecoder, TextEncoding},
 };
@@ -39,6 +41,14 @@ pub enum FramerConfig {
         #[serde(default = "default_max_frame")]
         max_frame: usize,
     },
+    MixedTextPlot {
+        #[serde(default = "default_true")]
+        strip_cr: bool,
+        #[serde(default = "default_max_line")]
+        max_line_len: usize,
+        #[serde(default = "default_max_frame")]
+        max_plot_frame: usize,
+    },
 }
 
 fn default_true() -> bool {
@@ -80,6 +90,15 @@ impl FramerConfig {
                 max_payload,
             })),
             FramerConfig::Cobs { max_frame } => Box::new(CobsFramer::new(max_frame)),
+            FramerConfig::MixedTextPlot {
+                strip_cr,
+                max_line_len,
+                max_plot_frame,
+            } => Box::new(MixedTextPlotFramer::new(MixedFramerConfig {
+                strip_cr,
+                max_line_len,
+                max_plot_frame,
+            })),
         }
     }
 }
@@ -109,6 +128,10 @@ pub enum DecoderConfig {
         #[serde(default)]
         format: PlotFormat,
     },
+    MixedTextPlot {
+        #[serde(default)]
+        encoding: TextEncoding,
+    },
 }
 
 fn default_sep() -> String {
@@ -144,6 +167,9 @@ impl DecoderConfig {
                 channels,
                 format,
             })),
+            DecoderConfig::MixedTextPlot { encoding } => {
+                Box::new(MixedTextPlotDecoder::new(MixedDecoderConfig { encoding }))
+            }
         }
     }
 }
@@ -240,6 +266,25 @@ mod tests {
         assert!(matches!(cfg, FramerConfig::Cobs { max_frame: 8192 }));
     }
 
+    #[test]
+    fn framer_mixed_serde() {
+        let json =
+            r#"{"MixedTextPlot":{"strip_cr":true,"max_line_len":4096,"max_plot_frame":8192}}"#;
+        let cfg: FramerConfig = serde_json::from_str(json).unwrap();
+        match cfg {
+            FramerConfig::MixedTextPlot {
+                strip_cr,
+                max_line_len,
+                max_plot_frame,
+            } => {
+                assert!(strip_cr);
+                assert_eq!(max_line_len, 4096);
+                assert_eq!(max_plot_frame, 8192);
+            }
+            _ => panic!("expected MixedTextPlot"),
+        }
+    }
+
     #[test]
     fn decoder_text_serde() {
         let cfg: DecoderConfig = serde_json::from_str(r#"{"Text":{"encoding":"Latin1"}}"#).unwrap();
@@ -290,6 +335,16 @@ mod tests {
         }
     }
 
+    #[test]
+    fn decoder_mixed_serde() {
+        let cfg: DecoderConfig =
+            serde_json::from_str(r#"{"MixedTextPlot":{"encoding":"Utf8"}}"#).unwrap();
+        match cfg {
+            DecoderConfig::MixedTextPlot { encoding } => assert_eq!(encoding, TextEncoding::Utf8),
+            _ => panic!("expected MixedTextPlot"),
+        }
+    }
+
     #[test]
     fn session_config_full_roundtrip() {
         let json = r#"{
@@ -327,6 +382,11 @@ mod tests {
                 max_payload: 65536,
             },
             FramerConfig::Cobs { max_frame: 1024 },
+            FramerConfig::MixedTextPlot {
+                strip_cr: true,
+                max_line_len: 256,
+                max_plot_frame: 1024,
+            },
         ] {
             let f = cfg.build();
             assert_eq!(f.pending_len(), 0);
@@ -365,5 +425,13 @@ mod tests {
             .name(),
             "Plot"
         );
+        assert_eq!(
+            DecoderConfig::MixedTextPlot {
+                encoding: TextEncoding::Utf8
+            }
+            .build()
+            .name(),
+            "MixedTextPlot"
+        );
     }
 }
diff --git a/crates/xserial-client/src/history.rs b/crates/xserial-client/src/history.rs
index f0a4d19..32d80cf 100644
--- a/crates/xserial-client/src/history.rs
+++ b/crates/xserial-client/src/history.rs
@@ -31,6 +31,12 @@ impl<T> RingBuffer<T> {
     pub fn clear(&mut self) {
         self.buf.clear();
     }
+    pub fn set_limit(&mut self, limit: usize) {
+        self.limit = limit;
+        while self.buf.len() > self.limit {
+            self.buf.pop_front();
+        }
+    }
     pub fn drain_recent(&self, count: usize) -> Vec<T>
     where
         T: Clone,
diff --git a/crates/xserial-core/src/frame/cobs.rs b/crates/xserial-core/src/frame/cobs.rs
index c3b350f..ec45828 100644
--- a/crates/xserial-core/src/frame/cobs.rs
+++ b/crates/xserial-core/src/frame/cobs.rs
@@ -87,7 +87,39 @@ impl Framer for CobsFramer {
 ///
 /// Returns `None` if the encoded data is invalid (e.g. an overhead byte
 /// points past the end of the buffer).
-fn cobs_decode(encoded: &[u8]) -> Option<Vec<u8>> {
+pub fn cobs_encode(payload: &[u8]) -> Vec<u8> {
+    if payload.is_empty() {
+        return vec![0x01];
+    }
+
+    let mut out = Vec::with_capacity(payload.len() + (payload.len() / 254) + 1);
+    let mut code_index = 0usize;
+    let mut code = 1u8;
+    out.push(0);
+
+    for &byte in payload {
+        if byte == 0 {
+            out[code_index] = code;
+            code_index = out.len();
+            out.push(0);
+            code = 1;
+        } else {
+            out.push(byte);
+            code = code.saturating_add(1);
+            if code == 0xFF {
+                out[code_index] = code;
+                code_index = out.len();
+                out.push(0);
+                code = 1;
+            }
+        }
+    }
+
+    out[code_index] = code;
+    out
+}
+
+pub fn cobs_decode(encoded: &[u8]) -> Option<Vec<u8>> {
     if encoded.is_empty() {
         return Some(Vec::new());
     }
@@ -127,6 +159,14 @@ fn cobs_decode(encoded: &[u8]) -> Option<Vec<u8>> {
 mod tests {
     use super::*;
 
+    #[test]
+    fn cobs_roundtrip_with_zeros() {
+        let payload = [0x11, 0x00, 0x22, 0x33, 0x00, 0x44];
+        let encoded = cobs_encode(&payload);
+        let decoded = cobs_decode(&encoded).unwrap();
+        assert_eq!(decoded, payload);
+    }
+
     // ── cobs_decode unit tests ──────────────────────────────────────
 
     #[test]
diff --git a/crates/xserial-core/src/frame/mixed.rs b/crates/xserial-core/src/frame/mixed.rs
new file mode 100644
index 0000000..0181bda
--- /dev/null
+++ b/crates/xserial-core/src/frame/mixed.rs
@@ -0,0 +1,215 @@
+use super::Framer;
+use crate::frame::cobs::cobs_decode;
+use crate::protocol::mixed::{
+    MIXED_FRAME_KIND_PLOT, MIXED_FRAME_KIND_TEXT, MIXED_PLOT_ESCAPE, MIXED_PLOT_MARKER,
+};
+
+#[derive(Debug, Clone)]
+pub struct MixedTextPlotConfig {
+    pub strip_cr: bool,
+    pub max_line_len: usize,
+    pub max_plot_frame: usize,
+}
+
+impl Default for MixedTextPlotConfig {
+    fn default() -> Self {
+        Self {
+            strip_cr: true,
+            max_line_len: 1024 * 1024,
+            max_plot_frame: 1024 * 1024,
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+enum State {
+    Text,
+    Escape,
+    Plot,
+}
+
+#[derive(Debug, Clone)]
+pub struct MixedTextPlotFramer {
+    state: State,
+    text_buf: Vec<u8>,
+    plot_buf: Vec<u8>,
+    plot_overflow: bool,
+    config: MixedTextPlotConfig,
+}
+
+impl MixedTextPlotFramer {
+    pub fn new(config: MixedTextPlotConfig) -> Self {
+        Self {
+            state: State::Text,
+            text_buf: Vec::new(),
+            plot_buf: Vec::new(),
+            plot_overflow: false,
+            config,
+        }
+    }
+
+    fn push_text_byte(&mut self, byte: u8, frames: &mut Vec<Vec<u8>>) {
+        if byte == b'\n' {
+            let mut line = std::mem::take(&mut self.text_buf);
+            if self.config.strip_cr && line.last() == Some(&b'\r') {
+                line.pop();
+            }
+            if line.len() <= self.config.max_line_len {
+                frames.push(tag_text_frame(line));
+            }
+            return;
+        }
+
+        if self.text_buf.len() < self.config.max_line_len.saturating_add(1) {
+            self.text_buf.push(byte);
+        }
+    }
+
+    fn finish_plot_frame(&mut self, frames: &mut Vec<Vec<u8>>) {
+        if self.plot_overflow || self.plot_buf.is_empty() {
+            self.plot_buf.clear();
+            self.plot_overflow = false;
+            return;
+        }
+
+        if let Some(decoded) = cobs_decode(&self.plot_buf) {
+            if decoded.len() <= self.config.max_plot_frame {
+                frames.push(tag_plot_frame(decoded));
+            }
+        }
+        self.plot_buf.clear();
+        self.plot_overflow = false;
+    }
+}
+
+impl Framer for MixedTextPlotFramer {
+    fn feed(&mut self, data: &[u8]) -> Vec<Vec<u8>> {
+        let mut frames = Vec::new();
+
+        for &byte in data {
+            match self.state {
+                State::Text => {
+                    if byte == MIXED_PLOT_ESCAPE {
+                        self.state = State::Escape;
+                    } else {
+                        self.push_text_byte(byte, &mut frames);
+                    }
+                }
+                State::Escape => {
+                    self.state = State::Text;
+                    match byte {
+                        MIXED_PLOT_ESCAPE => self.push_text_byte(MIXED_PLOT_ESCAPE, &mut frames),
+                        MIXED_PLOT_MARKER => {
+                            self.plot_buf.clear();
+                            self.plot_overflow = false;
+                            self.state = State::Plot;
+                        }
+                        _ => {
+                            self.push_text_byte(MIXED_PLOT_ESCAPE, &mut frames);
+                            self.push_text_byte(byte, &mut frames);
+                        }
+                    }
+                }
+                State::Plot => {
+                    if byte == 0x00 {
+                        self.finish_plot_frame(&mut frames);
+                        self.state = State::Text;
+                    } else if !self.plot_overflow {
+                        let max_encoded_len = self
+                            .config
+                            .max_plot_frame
+                            .saturating_add(self.config.max_plot_frame / 254)
+                            .saturating_add(8);
+                        if self.plot_buf.len() < max_encoded_len {
+                            self.plot_buf.push(byte);
+                        } else {
+                            self.plot_overflow = true;
+                        }
+                    }
+                }
+            }
+        }
+
+        frames
+    }
+
+    fn flush(&mut self) -> Option<Vec<u8>> {
+        if matches!(self.state, State::Escape) {
+            self.text_buf.push(MIXED_PLOT_ESCAPE);
+        }
+
+        self.state = State::Text;
+        self.plot_buf.clear();
+        self.plot_overflow = false;
+
+        if self.text_buf.is_empty() {
+            None
+        } else {
+            Some(tag_text_frame(std::mem::take(&mut self.text_buf)))
+        }
+    }
+
+    fn reset(&mut self) {
+        self.state = State::Text;
+        self.text_buf.clear();
+        self.plot_buf.clear();
+        self.plot_overflow = false;
+    }
+
+    fn pending_len(&self) -> usize {
+        self.text_buf.len() + self.plot_buf.len()
+    }
+}
+
+fn tag_text_frame(mut payload: Vec<u8>) -> Vec<u8> {
+    let mut frame = Vec::with_capacity(payload.len() + 1);
+    frame.push(MIXED_FRAME_KIND_TEXT);
+    frame.append(&mut payload);
+    frame
+}
+
+fn tag_plot_frame(mut payload: Vec<u8>) -> Vec<u8> {
+    let mut frame = Vec::with_capacity(payload.len() + 1);
+    frame.push(MIXED_FRAME_KIND_PLOT);
+    frame.append(&mut payload);
+    frame
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::frame::cobs::cobs_encode;
+
+    #[test]
+    fn mixed_text_lines_pass_through() {
+        let mut framer = MixedTextPlotFramer::new(MixedTextPlotConfig::default());
+        let frames = framer.feed(b"hello\nworld\n");
+        assert_eq!(frames, vec![b"\0hello".to_vec(), b"\0world".to_vec()]);
+    }
+
+    #[test]
+    fn mixed_escaped_rs_stays_in_text() {
+        let mut framer = MixedTextPlotFramer::new(MixedTextPlotConfig::default());
+        let frames = framer.feed(&[b'o', b'k', MIXED_PLOT_ESCAPE, MIXED_PLOT_ESCAPE, b'\n']);
+        assert_eq!(frames, vec![vec![0x00, b'o', b'k', MIXED_PLOT_ESCAPE]]);
+    }
+
+    #[test]
+    fn mixed_extracts_plot_packet() {
+        let mut framer = MixedTextPlotFramer::new(MixedTextPlotConfig::default());
+        let payload = [b'X', b'P', 1, 0, 8, 0, 1, 1, 0, 4, 0, 0, 0, 0, 0x80, 0x3f];
+        let encoded = cobs_encode(&payload);
+        let mut stream = vec![MIXED_PLOT_ESCAPE, MIXED_PLOT_MARKER];
+        stream.extend_from_slice(&encoded);
+        stream.push(0x00);
+        let frames = framer.feed(&stream);
+        assert_eq!(frames, vec![[vec![0x01], payload.to_vec()].concat()]);
+    }
+
+    #[test]
+    fn mixed_ignores_truncated_plot_on_flush() {
+        let mut framer = MixedTextPlotFramer::new(MixedTextPlotConfig::default());
+        let _ = framer.feed(&[MIXED_PLOT_ESCAPE, MIXED_PLOT_MARKER, 0x03, b'a']);
+        assert_eq!(framer.flush(), None);
+    }
+}
diff --git a/crates/xserial-core/src/frame/mod.rs b/crates/xserial-core/src/frame/mod.rs
index 3733f68..f0fd957 100644
--- a/crates/xserial-core/src/frame/mod.rs
+++ b/crates/xserial-core/src/frame/mod.rs
@@ -2,6 +2,7 @@ pub mod cobs;
 pub mod fixed;
 pub mod length;
 pub mod line;
+pub mod mixed;
 
 pub use crate::protocol::Endian;
 
diff --git a/crates/xserial-core/src/protocol/mixed.rs b/crates/xserial-core/src/protocol/mixed.rs
new file mode 100644
index 0000000..bc35530
--- /dev/null
+++ b/crates/xserial-core/src/protocol/mixed.rs
@@ -0,0 +1,221 @@
+use super::plot::{PlotConfig, PlotDecoder, PlotFormat, SampleType};
+use super::text::{TextDecoder, TextEncoding};
+use super::{DecodedData, Endian, ProtocolDecoder};
+
+pub const MIXED_PLOT_ESCAPE: u8 = 0x1E;
+pub const MIXED_PLOT_MARKER: u8 = b'P';
+pub const MIXED_FRAME_KIND_TEXT: u8 = 0x00;
+pub const MIXED_FRAME_KIND_PLOT: u8 = 0x01;
+
+const PLOT_PACKET_MAGIC: &[u8; 2] = b"XP";
+const PLOT_PACKET_VERSION: u8 = 1;
+const PLOT_PACKET_HEADER_LEN: usize = 13;
+
+#[derive(Debug, Clone, Copy)]
+pub struct MixedTextPlotConfig {
+    pub encoding: TextEncoding,
+}
+
+impl Default for MixedTextPlotConfig {
+    fn default() -> Self {
+        Self {
+            encoding: TextEncoding::Utf8,
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct MixedTextPlotDecoder {
+    config: MixedTextPlotConfig,
+}
+
+impl MixedTextPlotDecoder {
+    pub fn new(config: MixedTextPlotConfig) -> Self {
+        Self { config }
+    }
+
+    pub fn build_plot_packet(
+        sample_type: SampleType,
+        endian: Endian,
+        channels: usize,
+        format: PlotFormat,
+        samples_per_channel: usize,
+        payload: &[u8],
+    ) -> Vec<u8> {
+        let mut packet = Vec::with_capacity(PLOT_PACKET_HEADER_LEN + payload.len());
+        packet.extend_from_slice(PLOT_PACKET_MAGIC);
+        packet.push(PLOT_PACKET_VERSION);
+        packet.push(plot_format_to_u8(format));
+        packet.push(sample_type_to_u8(sample_type));
+        packet.push(match endian {
+            Endian::Little => 0,
+            Endian::Big => 1,
+        });
+        packet.push(channels.min(u8::MAX as usize) as u8);
+        packet.extend_from_slice(&(samples_per_channel.min(u16::MAX as usize) as u16).to_le_bytes());
+        packet.extend_from_slice(&(payload.len().min(u32::MAX as usize) as u32).to_le_bytes());
+        packet.extend_from_slice(payload);
+        packet
+    }
+
+    fn decode_plot(&self, frame: &[u8]) -> Option<DecodedData> {
+        if frame.len() < PLOT_PACKET_HEADER_LEN {
+            return None;
+        }
+        if &frame[..2] != PLOT_PACKET_MAGIC {
+            return None;
+        }
+        if frame[2] != PLOT_PACKET_VERSION {
+            return None;
+        }
+
+        let format = plot_format_from_u8(frame[3])?;
+        let sample_type = sample_type_from_u8(frame[4])?;
+        let endian = match frame[5] {
+            0 => Endian::Little,
+            1 => Endian::Big,
+            _ => return None,
+        };
+        let channels = frame[6] as usize;
+        let samples_per_channel = u16::from_le_bytes([frame[7], frame[8]]) as usize;
+        let payload_len = u32::from_le_bytes([frame[9], frame[10], frame[11], frame[12]]) as usize;
+        let payload = frame.get(PLOT_PACKET_HEADER_LEN..PLOT_PACKET_HEADER_LEN + payload_len)?;
+
+        let num_channels = match format {
+            PlotFormat::XY => 2,
+            _ => channels.max(1),
+        };
+        if matches!(format, PlotFormat::XY) && channels != 2 {
+            return None;
+        }
+
+        let expected_len = sample_type
+            .byte_size()
+            .checked_mul(num_channels)?
+            .checked_mul(samples_per_channel)?;
+        if payload.len() != expected_len {
+            return None;
+        }
+
+        let decoder = PlotDecoder::new(PlotConfig {
+            sample_type,
+            endian,
+            channels: num_channels,
+            format,
+        });
+        decoder.decode(payload)
+    }
+}
+
+impl ProtocolDecoder for MixedTextPlotDecoder {
+    fn name(&self) -> &str {
+        "MixedTextPlot"
+    }
+
+    fn decode(&self, frame: &[u8]) -> Option<DecodedData> {
+        let (&kind, payload) = frame.split_first()?;
+        match kind {
+            MIXED_FRAME_KIND_TEXT => TextDecoder::new(self.config.encoding).decode(payload),
+            MIXED_FRAME_KIND_PLOT => self.decode_plot(payload),
+            _ => None,
+        }
+    }
+}
+
+fn plot_format_to_u8(format: PlotFormat) -> u8 {
+    match format {
+        PlotFormat::Interleaved => 0,
+        PlotFormat::Block => 1,
+        PlotFormat::XY => 2,
+    }
+}
+
+fn plot_format_from_u8(value: u8) -> Option<PlotFormat> {
+    match value {
+        0 => Some(PlotFormat::Interleaved),
+        1 => Some(PlotFormat::Block),
+        2 => Some(PlotFormat::XY),
+        _ => None,
+    }
+}
+
+fn sample_type_to_u8(sample_type: SampleType) -> u8 {
+    match sample_type {
+        SampleType::I8 => 0,
+        SampleType::U8 => 1,
+        SampleType::I16 => 2,
+        SampleType::U16 => 3,
+        SampleType::I32 => 4,
+        SampleType::U32 => 5,
+        SampleType::I64 => 6,
+        SampleType::U64 => 7,
+        SampleType::F32 => 8,
+        SampleType::F64 => 9,
+    }
+}
+
+fn sample_type_from_u8(value: u8) -> Option<SampleType> {
+    match value {
+        0 => Some(SampleType::I8),
+        1 => Some(SampleType::U8),
+        2 => Some(SampleType::I16),
+        3 => Some(SampleType::U16),
+        4 => Some(SampleType::I32),
+        5 => Some(SampleType::U32),
+        6 => Some(SampleType::I64),
+        7 => Some(SampleType::U64),
+        8 => Some(SampleType::F32),
+        9 => Some(SampleType::F64),
+        _ => None,
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn mixed_decoder_decodes_text_frame() {
+        let decoder = MixedTextPlotDecoder::new(MixedTextPlotConfig::default());
+        let frame = b"\0hello";
+        assert!(matches!(decoder.decode(frame), Some(DecodedData::Text(ref s)) if s == "hello"));
+    }
+
+    #[test]
+    fn mixed_decoder_decodes_plot_frame() {
+        let decoder = MixedTextPlotDecoder::new(MixedTextPlotConfig::default());
+        let payload = [0x00, 0x00, 0x80, 0x3f, 0x00, 0x00, 0x00, 0x40];
+        let packet = MixedTextPlotDecoder::build_plot_packet(
+            SampleType::F32,
+            Endian::Little,
+            1,
+            PlotFormat::Interleaved,
+            2,
+            &payload,
+        );
+        let frame = [vec![MIXED_FRAME_KIND_PLOT], packet].concat();
+        let decoded = decoder.decode(&frame).unwrap();
+        match decoded {
+            DecodedData::Plot(frame) => {
+                assert_eq!(frame.channels.len(), 1);
+                assert_eq!(frame.channels[0], vec![1.0, 2.0]);
+            }
+            other => panic!("expected Plot, got {other:?}"),
+        }
+    }
+
+    #[test]
+    fn mixed_decoder_rejects_bad_payload_length() {
+        let decoder = MixedTextPlotDecoder::new(MixedTextPlotConfig::default());
+        let packet = MixedTextPlotDecoder::build_plot_packet(
+            SampleType::F32,
+            Endian::Little,
+            1,
+            PlotFormat::Interleaved,
+            2,
+            &[0x00, 0x00, 0x80, 0x3f],
+        );
+        let frame = [vec![MIXED_FRAME_KIND_PLOT], packet].concat();
+        assert!(decoder.decode(&frame).is_none());
+    }
+}
diff --git a/crates/xserial-core/src/protocol/mod.rs b/crates/xserial-core/src/protocol/mod.rs
index 8ca7fc6..0bbdbe0 100644
--- a/crates/xserial-core/src/protocol/mod.rs
+++ b/crates/xserial-core/src/protocol/mod.rs
@@ -1,4 +1,5 @@
 pub mod hex;
+pub mod mixed;
 pub mod plot;
 pub mod text;
 
diff --git a/crates/xserial-core/src/protocol/plot.rs b/crates/xserial-core/src/protocol/plot.rs
index 7a97507..352773c 100644
--- a/crates/xserial-core/src/protocol/plot.rs
+++ b/crates/xserial-core/src/protocol/plot.rs
@@ -78,6 +78,7 @@ pub struct PlotFrame {
     pub channels: Vec<Vec<f64>>,
     pub raw: Vec<u8>,
     pub sample_type: SampleType,
+    pub format: PlotFormat,
 }
 
 impl PlotFrame {
@@ -245,6 +246,7 @@ impl ProtocolDecoder for PlotDecoder {
             channels,
             raw: frame.to_vec(),
             sample_type: self.config.sample_type,
+            format: self.config.format,
         }))
     }
 }
@@ -490,6 +492,7 @@ mod tests {
             channels: vec![],
             raw: vec![],
             sample_type: SampleType::U8,
+            format: PlotFormat::Interleaved,
         };
         assert_eq!(frame.sample_count(), 0);
     }
@@ -507,6 +510,7 @@ mod tests {
         match result {
             DecodedData::Plot(frame) => {
                 assert_eq!(frame.raw, data);
+                assert_eq!(frame.format, PlotFormat::Interleaved);
             }
             other => panic!("expected Plot, got {:?}", other),
         }
diff --git a/crates/xserial-core/src/transport/mod.rs b/crates/xserial-core/src/transport/mod.rs
index 783d36a..ec564cb 100644
--- a/crates/xserial-core/src/transport/mod.rs
+++ b/crates/xserial-core/src/transport/mod.rs
@@ -4,7 +4,9 @@ use tokio::io::{AsyncRead, AsyncWrite};
 use tracing::info;
 
 use crate::error::Result;
-use crate::transport::serial::SerialTransport;
+use crate::transport::serial::{
+    SerialDataBits, SerialFlowControl, SerialParity, SerialStopBits, SerialTransport,
+};
 use crate::transport::tcp::TcpTransport;
 use crate::transport::udp::UdpTransport;
 
@@ -12,6 +14,22 @@ pub mod serial;
 pub mod tcp;
 pub mod udp;
 
+fn default_serial_data_bits() -> SerialDataBits {
+    SerialDataBits::Eight
+}
+
+fn default_serial_parity() -> SerialParity {
+    SerialParity::None
+}
+
+fn default_serial_stop_bits() -> SerialStopBits {
+    SerialStopBits::One
+}
+
+fn default_serial_flow_control() -> SerialFlowControl {
+    SerialFlowControl::None
+}
+
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
 pub enum TransportType {
     Serial,
@@ -34,6 +52,14 @@ pub enum TransportConfig {
     Serial {
         port: String,
         baud_rate: u32,
+        #[serde(default = "default_serial_data_bits")]
+        data_bits: SerialDataBits,
+        #[serde(default = "default_serial_parity")]
+        parity: SerialParity,
+        #[serde(default = "default_serial_stop_bits")]
+        stop_bits: SerialStopBits,
+        #[serde(default = "default_serial_flow_control")]
+        flow_control: SerialFlowControl,
     },
     Tcp {
         addr: String,
@@ -63,9 +89,21 @@ pub enum Connection {
 impl Connection {
     pub fn new(config: TransportConfig) -> Self {
         match config {
-            TransportConfig::Serial { port, baud_rate } => {
-                Connection::Serial(SerialTransport::new(port, baud_rate))
-            }
+            TransportConfig::Serial {
+                port,
+                baud_rate,
+                data_bits,
+                parity,
+                stop_bits,
+                flow_control,
+            } => Connection::Serial(SerialTransport::new(
+                port,
+                baud_rate,
+                data_bits,
+                parity,
+                stop_bits,
+                flow_control,
+            )),
             TransportConfig::Tcp { addr } => Connection::Tcp(TcpTransport::new(addr)),
             TransportConfig::Udp {
                 bind_addr,
@@ -170,6 +208,20 @@ impl AsyncWrite for Connection {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::transport::serial::{
+        SerialDataBits, SerialFlowControl, SerialParity, SerialStopBits,
+    };
+
+    fn serial_config(port: &str, baud_rate: u32) -> TransportConfig {
+        TransportConfig::Serial {
+            port: port.into(),
+            baud_rate,
+            data_bits: SerialDataBits::Eight,
+            parity: SerialParity::None,
+            stop_bits: SerialStopBits::One,
+            flow_control: SerialFlowControl::None,
+        }
+    }
 
     #[test]
     fn test_transport_type_display() {
@@ -256,6 +308,10 @@ mod tests {
         let cfg = TransportConfig::Serial {
             port: "COM1".into(),
             baud_rate: 115200,
+            data_bits: SerialDataBits::Eight,
+            parity: SerialParity::None,
+            stop_bits: SerialStopBits::One,
+            flow_control: SerialFlowControl::None,
         };
         let _ = format!("{:?}", cfg);
 
@@ -273,10 +329,7 @@ mod tests {
 
     #[test]
     fn test_transport_config_clone() {
-        let original = TransportConfig::Serial {
-            port: "COM1".into(),
-            baud_rate: 115200,
-        };
+        let original = serial_config("COM1", 115200);
         let cloned = original.clone();
         assert_eq!(format!("{:?}", original), format!("{:?}", cloned));
 
@@ -296,13 +349,14 @@ mod tests {
 
     #[test]
     fn test_transport_config_serialize_serial() {
-        let cfg = TransportConfig::Serial {
-            port: "COM1".into(),
-            baud_rate: 115200,
-        };
+        let cfg = serial_config("COM1", 115200);
         let json = serde_json::to_string(&cfg).unwrap();
         assert!(json.contains("COM1"));
         assert!(json.contains("115200"));
+        assert!(json.contains("data_bits"));
+        assert!(json.contains("parity"));
+        assert!(json.contains("stop_bits"));
+        assert!(json.contains("flow_control"));
     }
 
     #[test]
@@ -310,9 +364,44 @@ mod tests {
         let json = r#"{"Serial":{"port":"COM1","baud_rate":9600}}"#;
         let cfg: TransportConfig = serde_json::from_str(json).unwrap();
         match cfg {
-            TransportConfig::Serial { port, baud_rate } => {
+            TransportConfig::Serial {
+                port,
+                baud_rate,
+                data_bits,
+                parity,
+                stop_bits,
+                flow_control,
+            } => {
                 assert_eq!(port, "COM1");
                 assert_eq!(baud_rate, 9600);
+                assert_eq!(data_bits, SerialDataBits::Eight);
+                assert_eq!(parity, SerialParity::None);
+                assert_eq!(stop_bits, SerialStopBits::One);
+                assert_eq!(flow_control, SerialFlowControl::None);
+            }
+            _ => panic!("expected Serial variant"),
+        }
+    }
+
+    #[test]
+    fn test_transport_config_deserialize_serial_with_explicit_options() {
+        let json = r#"{"Serial":{"port":"COM2","baud_rate":57600,"data_bits":"Seven","parity":"Even","stop_bits":"Two","flow_control":"Hardware"}}"#;
+        let cfg: TransportConfig = serde_json::from_str(json).unwrap();
+        match cfg {
+            TransportConfig::Serial {
+                port,
+                baud_rate,
+                data_bits,
+                parity,
+                stop_bits,
+                flow_control,
+            } => {
+                assert_eq!(port, "COM2");
+                assert_eq!(baud_rate, 57600);
+                assert_eq!(data_bits, SerialDataBits::Seven);
+                assert_eq!(parity, SerialParity::Even);
+                assert_eq!(stop_bits, SerialStopBits::Two);
+                assert_eq!(flow_control, SerialFlowControl::Hardware);
             }
             _ => panic!("expected Serial variant"),
         }
@@ -393,10 +482,7 @@ mod tests {
     #[test]
     fn test_transport_config_roundtrip() {
         let configs = vec![
-            TransportConfig::Serial {
-                port: "COM3".into(),
-                baud_rate: 57600,
-            },
+            serial_config("COM3", 57600),
             TransportConfig::Tcp {
                 addr: "10.0.0.1:9999".into(),
             },
@@ -425,10 +511,7 @@ mod tests {
 
     #[test]
     fn test_connection_new_serial() {
-        let conn = Connection::new(TransportConfig::Serial {
-            port: "COM1".into(),
-            baud_rate: 115200,
-        });
+        let conn = Connection::new(serial_config("COM1", 115200));
         assert_eq!(conn.transport_type(), TransportType::Serial);
         assert_eq!(conn.name(), "COM1");
         assert!(!conn.is_connected());
@@ -468,10 +551,7 @@ mod tests {
 
     #[test]
     fn test_connection_is_connected_default() {
-        let serial = Connection::new(TransportConfig::Serial {
-            port: "COM1".into(),
-            baud_rate: 9600,
-        });
+        let serial = Connection::new(serial_config("COM1", 9600));
         let tcp = Connection::new(TransportConfig::Tcp {
             addr: "127.0.0.1:8080".into(),
         });
@@ -486,10 +566,7 @@ mod tests {
 
     #[test]
     fn test_connection_debug() {
-        let serial = Connection::new(TransportConfig::Serial {
-            port: "COM1".into(),
-            baud_rate: 115200,
-        });
+        let serial = Connection::new(serial_config("COM1", 115200));
         let tcp = Connection::new(TransportConfig::Tcp {
             addr: "127.0.0.1:8080".into(),
         });
@@ -515,10 +592,7 @@ mod tests {
     }
 
     fn serial_conn() -> Connection {
-        Connection::new(TransportConfig::Serial {
-            port: "COM1".into(),
-            baud_rate: 115200,
-        })
+        Connection::new(serial_config("COM1", 115200))
     }
 
     fn tcp_conn() -> Connection {
diff --git a/crates/xserial-core/src/transport/serial.rs b/crates/xserial-core/src/transport/serial.rs
index fffedb4..02a8177 100644
--- a/crates/xserial-core/src/transport/serial.rs
+++ b/crates/xserial-core/src/transport/serial.rs
@@ -1,24 +1,107 @@
 use async_trait::async_trait;
 use tokio::io::{AsyncRead, AsyncWrite, ReadBuf};
-use tokio_serial::{SerialPortBuilderExt, SerialStream};
+use tokio_serial::{DataBits, FlowControl, Parity, SerialPortBuilderExt, SerialStream, StopBits};
 use tracing::{debug, info, warn};
 
 use super::{Transport, TransportType};
 use crate::error::Result;
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
+pub enum SerialDataBits {
+    Five,
+    Six,
+    Seven,
+    Eight,
+}
+
+impl From<SerialDataBits> for DataBits {
+    fn from(value: SerialDataBits) -> Self {
+        match value {
+            SerialDataBits::Five => DataBits::Five,
+            SerialDataBits::Six => DataBits::Six,
+            SerialDataBits::Seven => DataBits::Seven,
+            SerialDataBits::Eight => DataBits::Eight,
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
+pub enum SerialParity {
+    None,
+    Odd,
+    Even,
+}
+
+impl From<SerialParity> for Parity {
+    fn from(value: SerialParity) -> Self {
+        match value {
+            SerialParity::None => Parity::None,
+            SerialParity::Odd => Parity::Odd,
+            SerialParity::Even => Parity::Even,
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
+pub enum SerialStopBits {
+    One,
+    Two,
+}
+
+impl From<SerialStopBits> for StopBits {
+    fn from(value: SerialStopBits) -> Self {
+        match value {
+            SerialStopBits::One => StopBits::One,
+            SerialStopBits::Two => StopBits::Two,
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
+pub enum SerialFlowControl {
+    None,
+    Software,
+    Hardware,
+}
+
+impl From<SerialFlowControl> for FlowControl {
+    fn from(value: SerialFlowControl) -> Self {
+        match value {
+            SerialFlowControl::None => FlowControl::None,
+            SerialFlowControl::Software => FlowControl::Software,
+            SerialFlowControl::Hardware => FlowControl::Hardware,
+        }
+    }
+}
+
 #[derive(Debug)]
 pub struct SerialTransport {
     port: Option<SerialStream>,
     port_name: String,
     baud_rate: u32,
+    data_bits: SerialDataBits,
+    parity: SerialParity,
+    stop_bits: SerialStopBits,
+    flow_control: SerialFlowControl,
 }
 
 impl SerialTransport {
-    pub fn new(port_name: String, baud_rate: u32) -> Self {
+    pub fn new(
+        port_name: String,
+        baud_rate: u32,
+        data_bits: SerialDataBits,
+        parity: SerialParity,
+        stop_bits: SerialStopBits,
+        flow_control: SerialFlowControl,
+    ) -> Self {
         Self {
             port: None,
             port_name,
             baud_rate,
+            data_bits,
+            parity,
+            stop_bits,
+            flow_control,
         }
     }
 
@@ -39,6 +122,22 @@ impl SerialTransport {
     pub fn baud_rate(&self) -> u32 {
         self.baud_rate
     }
+
+    pub fn data_bits(&self) -> SerialDataBits {
+        self.data_bits
+    }
+
+    pub fn parity(&self) -> SerialParity {
+        self.parity
+    }
+
+    pub fn stop_bits(&self) -> SerialStopBits {
+        self.stop_bits
+    }
+
+    pub fn flow_control(&self) -> SerialFlowControl {
+        self.flow_control
+    }
 }
 
 impl AsyncRead for SerialTransport {
@@ -113,11 +212,20 @@ impl Transport for SerialTransport {
         }
 
         info!(
-            "Opening serial port {} at {} baud",
-            self.port_name, self.baud_rate
+            "Opening serial port {} at {} baud ({:?}, {:?}, {:?}, {:?})",
+            self.port_name,
+            self.baud_rate,
+            self.data_bits,
+            self.parity,
+            self.stop_bits,
+            self.flow_control
         );
 
         let port = tokio_serial::new(&self.port_name, self.baud_rate)
+            .data_bits(self.data_bits.into())
+            .parity(self.parity.into())
+            .stop_bits(self.stop_bits.into())
+            .flow_control(self.flow_control.into())
             .open_native_async()
             .map_err(|e| {
                 crate::error::Error::ConnectionFailed(format!(
@@ -167,33 +275,72 @@ mod tests {
 
     #[test]
     fn test_new() {
-        let transport = SerialTransport::new("COM1".into(), 115200);
+        let transport = SerialTransport::new(
+            "COM1".into(),
+            115200,
+            SerialDataBits::Eight,
+            SerialParity::None,
+            SerialStopBits::One,
+            SerialFlowControl::None,
+        );
         assert_eq!(transport.port_name(), "COM1");
         assert_eq!(transport.baud_rate(), 115200);
     }
 
     #[test]
     fn test_new_different_params() {
-        let transport = SerialTransport::new("COM3".into(), 9600);
+        let transport = SerialTransport::new(
+            "COM3".into(),
+            9600,
+            SerialDataBits::Seven,
+            SerialParity::Even,
+            SerialStopBits::Two,
+            SerialFlowControl::Hardware,
+        );
         assert_eq!(transport.port_name(), "COM3");
         assert_eq!(transport.baud_rate(), 9600);
+        assert_eq!(transport.data_bits(), SerialDataBits::Seven);
+        assert_eq!(transport.parity(), SerialParity::Even);
+        assert_eq!(transport.stop_bits(), SerialStopBits::Two);
+        assert_eq!(transport.flow_control(), SerialFlowControl::Hardware);
     }
 
     #[test]
     fn test_name() {
-        let transport = SerialTransport::new("COM1".into(), 115200);
+        let transport = SerialTransport::new(
+            "COM1".into(),
+            115200,
+            SerialDataBits::Eight,
+            SerialParity::None,
+            SerialStopBits::One,
+            SerialFlowControl::None,
+        );
         assert_eq!(transport.name(), "COM1");
     }
 
     #[test]
     fn test_transport_type() {
-        let transport = SerialTransport::new("COM1".into(), 115200);
+        let transport = SerialTransport::new(
+            "COM1".into(),
+            115200,
+            SerialDataBits::Eight,
+            SerialParity::None,
+            SerialStopBits::One,
+            SerialFlowControl::None,
+        );
         assert_eq!(transport.transport_type(), TransportType::Serial);
     }
 
     #[test]
     fn test_is_connected_false_by_default() {
-        let transport = SerialTransport::new("COM1".into(), 115200);
+        let transport = SerialTransport::new(
+            "COM1".into(),
+            115200,
+            SerialDataBits::Eight,
+            SerialParity::None,
+            SerialStopBits::One,
+            SerialFlowControl::None,
+        );
         assert!(!transport.is_connected());
     }
 
@@ -214,7 +361,14 @@ mod tests {
 
     #[tokio::test]
     async fn test_poll_read_not_connected() {
-        let mut transport = SerialTransport::new("COM1".into(), 115200);
+        let mut transport = SerialTransport::new(
+            "COM1".into(),
+            115200,
+            SerialDataBits::Eight,
+            SerialParity::None,
+            SerialStopBits::One,
+            SerialFlowControl::None,
+        );
         let pinned = Pin::new(&mut transport);
         let mut buf_data = [0u8; 16];
         let mut buf = ReadBuf::new(&mut buf_data);
@@ -230,7 +384,14 @@ mod tests {
 
     #[tokio::test]
     async fn test_poll_write_not_connected() {
-        let mut transport = SerialTransport::new("COM1".into(), 115200);
+        let mut transport = SerialTransport::new(
+            "COM1".into(),
+            115200,
+            SerialDataBits::Eight,
+            SerialParity::None,
+            SerialStopBits::One,
+            SerialFlowControl::None,
+        );
         let pinned = Pin::new(&mut transport);
         let data = b"hello";
         let waker = noop_waker();
@@ -243,7 +404,14 @@ mod tests {
 
     #[tokio::test]
     async fn test_poll_flush_not_connected() {
-        let mut transport = SerialTransport::new("COM1".into(), 115200);
+        let mut transport = SerialTransport::new(
+            "COM1".into(),
+            115200,
+            SerialDataBits::Eight,
+            SerialParity::None,
+            SerialStopBits::One,
+            SerialFlowControl::None,
+        );
         let pinned = Pin::new(&mut transport);
         let waker = noop_waker();
         let mut cx = Context::from_waker(&waker);
@@ -255,7 +423,14 @@ mod tests {
 
     #[tokio::test]
     async fn test_poll_shutdown_not_connected() {
-        let mut transport = SerialTransport::new("COM1".into(), 115200);
+        let mut transport = SerialTransport::new(
+            "COM1".into(),
+            115200,
+            SerialDataBits::Eight,
+            SerialParity::None,
+            SerialStopBits::One,
+            SerialFlowControl::None,
+        );
         let pinned = Pin::new(&mut transport);
         let waker = noop_waker();
         let mut cx = Context::from_waker(&waker);
@@ -269,19 +444,40 @@ mod tests {
 
     #[test]
     fn test_transport_name() {
-        let transport = SerialTransport::new("COM1".into(), 115200);
+        let transport = SerialTransport::new(
+            "COM1".into(),
+            115200,
+            SerialDataBits::Eight,
+            SerialParity::None,
+            SerialStopBits::One,
+            SerialFlowControl::None,
+        );
         assert_eq!(transport.name(), "COM1");
     }
 
     #[test]
     fn test_transport_transport_type() {
-        let transport = SerialTransport::new("COM1".into(), 115200);
+        let transport = SerialTransport::new(
+            "COM1".into(),
+            115200,
+            SerialDataBits::Eight,
+            SerialParity::None,
+            SerialStopBits::One,
+            SerialFlowControl::None,
+        );
         assert_eq!(transport.transport_type(), TransportType::Serial);
     }
 
     #[test]
     fn test_transport_is_connected() {
-        let transport = SerialTransport::new("COM1".into(), 115200);
+        let transport = SerialTransport::new(
+            "COM1".into(),
+            115200,
+            SerialDataBits::Eight,
+            SerialParity::None,
+            SerialStopBits::One,
+            SerialFlowControl::None,
+        );
         assert!(!transport.is_connected());
     }
 }
diff --git a/crates/xserial-core/tests/pipeline.rs b/crates/xserial-core/tests/pipeline.rs
index d63ffcc..f6c9217 100644
--- a/crates/xserial-core/tests/pipeline.rs
+++ b/crates/xserial-core/tests/pipeline.rs
@@ -6,17 +6,23 @@ use tokio::time::timeout;
 
 use xserial_core::frame::{
     Endian, Framer,
+    cobs::cobs_encode as raw_cobs_encode,
     cobs::CobsFramer,
     fixed::FixedLengthFramer,
     length::{LengthConfig, LengthPrefixedFramer},
     line::{LineConfig, LineFramer},
+    mixed::{MixedTextPlotConfig as MixedFramerConfig, MixedTextPlotFramer},
 };
 use xserial_core::protocol::{
     DecodedData, ProtocolDecoder,
     hex::{HexConfig, HexDecoder},
+    mixed::{MIXED_PLOT_ESCAPE, MIXED_PLOT_MARKER, MixedTextPlotConfig, MixedTextPlotDecoder},
     plot::{PlotConfig, PlotDecoder, PlotFormat, SampleType},
     text::{TextDecoder, TextEncoding},
 };
+use xserial_core::transport::serial::{
+    SerialDataBits, SerialFlowControl, SerialParity, SerialStopBits,
+};
 use xserial_core::transport::{Connection, TransportConfig, TransportType};
 
 const TEST_TIMEOUT: Duration = Duration::from_secs(5);
@@ -256,6 +262,58 @@ async fn tcp_fixed_plot_f32() {
     server.await.unwrap();
 }
 
+#[tokio::test]
+async fn tcp_mixed_text_and_plot_single_stream() {
+    let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
+    let addr = listener.local_addr().unwrap().to_string();
+
+    let server = tokio::spawn(async move {
+        let (mut stream, _) = listener.accept().await.unwrap();
+        let payload = [
+            0x00, 0x00, 0x80, 0x3f, // 1.0
+            0x00, 0x00, 0x00, 0x40, // 2.0
+        ];
+        let packet = MixedTextPlotDecoder::build_plot_packet(
+            SampleType::F32,
+            Endian::Little,
+            1,
+            PlotFormat::Interleaved,
+            2,
+            &payload,
+        );
+        let mut mixed = b"status ok\n".to_vec();
+        mixed.push(MIXED_PLOT_ESCAPE);
+        mixed.push(MIXED_PLOT_MARKER);
+        mixed.extend_from_slice(&raw_cobs_encode(&packet));
+        mixed.push(0x00);
+        mixed.extend_from_slice(b"done\n");
+        stream.write_all(&mixed).await.unwrap();
+    });
+
+    let mut conn = Connection::new(TransportConfig::Tcp { addr });
+    conn.connect().await.unwrap();
+
+    let mut framer = MixedTextPlotFramer::new(MixedFramerConfig::default());
+    let frames = read_to_framer(&mut conn, &mut framer).await;
+    conn.disconnect().await.unwrap();
+
+    let decoder = MixedTextPlotDecoder::new(MixedTextPlotConfig::default());
+    let results: Vec<DecodedData> = frames
+        .iter()
+        .filter_map(|f| decoder.decode(f))
+        .collect();
+
+    assert_eq!(results.len(), 3);
+    assert!(matches!(&results[0], DecodedData::Text(s) if s == "status ok"));
+    match &results[1] {
+        DecodedData::Plot(frame) => assert_eq!(frame.channels[0], vec![1.0, 2.0]),
+        other => panic!("expected Plot, got {other:?}"),
+    }
+    assert!(matches!(&results[2], DecodedData::Text(s) if s == "done"));
+
+    server.await.unwrap();
+}
+
 #[tokio::test]
 async fn tcp_fixed_plot_two_channel_u16() {
     let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
@@ -629,6 +687,10 @@ async fn connection_transport_type_dispatch() {
     let serial = Connection::new(TransportConfig::Serial {
         port: "COM1".into(),
         baud_rate: 115200,
+        data_bits: SerialDataBits::Eight,
+        parity: SerialParity::None,
+        stop_bits: SerialStopBits::One,
+        flow_control: SerialFlowControl::None,
     });
     let tcp = Connection::new(TransportConfig::Tcp {
         addr: "127.0.0.1:8080".into(),
diff --git a/crates/xserial-gui/src/app.rs b/crates/xserial-gui/src/app.rs
index 3d9a2ed..8c98348 100644
--- a/crates/xserial-gui/src/app.rs
+++ b/crates/xserial-gui/src/app.rs
@@ -1,7 +1,8 @@
 use std::sync::mpsc;
+use std::time::Duration;
 
-use crate::buffers::{HexBuffer, TextBuffer};
-use crate::panels::{config, console, hex_view, sidebar};
+use crate::buffers::{HexBuffer, PlotBuffer, TextBuffer};
+use crate::panels::{config, console, hex_view, plot_view, sidebar};
 use egui::{Color32, Layout, Panel, Pos2, Rect, TextEdit, UiBuilder};
 use xserial_client::SessionManager;
 use xserial_client::config::SessionConfig;
@@ -31,6 +32,7 @@ impl ConnectionStatus {
 pub enum View {
     Text,
     Hex,
+    Plot,
 }
 
 #[derive(Clone, Copy, PartialEq)]
@@ -52,6 +54,8 @@ pub struct SessionTab {
     pub status: ConnectionStatus,
     pub console: TextBuffer,
     pub hex: HexBuffer,
+    pub plot: PlotBuffer,
+    pub plot_view: plot_view::PlotViewState,
     pub view: View,
     pub auto_reconnect: bool,
     pub send_input: String,
@@ -131,8 +135,9 @@ impl XserialApp {
             let history_limit = session_config.history_limit;
             tab.session_config = session_config.clone();
             tab.auto_reconnect = session_config.auto_reconnect;
-            tab.console = TextBuffer::new(history_limit);
-            tab.hex = HexBuffer::new(history_limit);
+            tab.console.set_limit(history_limit);
+            tab.hex.set_limit(history_limit);
+            tab.plot.set_limit(history_limit);
             tab.status = ConnectionStatus::Connecting;
             tab.send_status = Some(String::from("Session reconfigured"));
         }
@@ -173,7 +178,8 @@ impl XserialApp {
                         match &entry.data {
                             DecodedData::Text(_) => tab.console.push(&entry),
                             DecodedData::Hex(_) => tab.hex.push(&entry),
-                            DecodedData::Binary(_) | DecodedData::Plot(_) => {}
+                            DecodedData::Plot(_) => tab.plot.push(&entry),
+                            DecodedData::Binary(_) => {}
                         }
                     }
                 }
@@ -181,6 +187,15 @@ impl XserialApp {
         }
     }
 
+    fn wants_live_plot_repaint(&self) -> bool {
+        self.tabs
+            .get(self.active)
+            .map(|tab| {
+                matches!(tab.view, View::Plot) && matches!(tab.status, ConnectionStatus::Connected)
+            })
+            .unwrap_or(false)
+    }
+
     fn render_config_window(&mut self, ctx: &egui::Context) {
         if !self.config_open {
             return;
@@ -215,6 +230,8 @@ impl XserialApp {
                     status: ConnectionStatus::Connecting,
                     console: TextBuffer::new(history_limit),
                     hex: HexBuffer::new(history_limit),
+                    plot: PlotBuffer::new(history_limit),
+                    plot_view: plot_view::PlotViewState::default(),
                     view: View::Text,
                     auto_reconnect,
                     send_input: String::new(),
@@ -296,6 +313,12 @@ impl XserialApp {
                     if ui.selectable_label(tab.view == View::Hex, "Hex").clicked() {
                         tab.view = View::Hex;
                     }
+                    if ui
+                        .selectable_label(tab.view == View::Plot, "Plot")
+                        .clicked()
+                    {
+                        tab.view = View::Plot;
+                    }
                 });
 
                 if render_session_controls(ui, &manager, tab) {
@@ -331,6 +354,7 @@ impl XserialApp {
                     |ui| match tab.view {
                         View::Text => console::render(ui, &tab.console, *display),
                         View::Hex => hex_view::render(ui, &tab.hex, *display),
+                        View::Plot => plot_view::render(ui, &tab.plot, tab.id, &mut tab.plot_view),
                     },
                 );
 
@@ -354,6 +378,9 @@ impl eframe::App for XserialApp {
 
     fn ui(&mut self, ui: &mut egui::Ui, _frame: &mut eframe::Frame) {
         self.drain_events();
+        if self.wants_live_plot_repaint() {
+            ui.ctx().request_repaint_after(Duration::from_millis(16));
+        }
         self.render_config_window(ui.ctx());
         self.render_sidebar(ui);
         self.render_main_panel(ui);
@@ -404,6 +431,13 @@ fn render_session_controls(
             configure_clicked = true;
         }
 
+        if ui.button("Clear").clicked() {
+            tab.console.clear();
+            tab.hex.clear();
+            tab.plot.clear();
+            tab.send_status = Some(String::from("Cleared"));
+        }
+
         let response = ui.checkbox(&mut tab.auto_reconnect, "Auto reconnect");
         if response.changed() {
             if let Some(handle) = manager.get(tab.id) {
diff --git a/crates/xserial-gui/src/buffers.rs b/crates/xserial-gui/src/buffers.rs
index a1a5e6b..a59d32b 100644
--- a/crates/xserial-gui/src/buffers.rs
+++ b/crates/xserial-gui/src/buffers.rs
@@ -1,7 +1,9 @@
+use std::collections::VecDeque;
 use std::time::{Duration, Instant};
 use xserial_client::RingBuffer;
 use xserial_client::event::DecodedEntry;
 use xserial_core::protocol::DecodedData;
+use xserial_core::protocol::plot::{PlotFormat, PlotFrame};
 
 #[derive(Clone)]
 pub enum LineDirection {
@@ -52,6 +54,14 @@ impl TextBuffer {
     pub fn iter(&self) -> impl Iterator<Item = &ConsoleLine> {
         self.lines.iter()
     }
+
+    pub fn clear(&mut self) {
+        self.lines.clear();
+    }
+
+    pub fn set_limit(&mut self, limit: usize) {
+        self.lines.set_limit(limit);
+    }
 }
 
 #[derive(Clone)]
@@ -128,4 +138,339 @@ impl HexBuffer {
     pub fn iter(&self) -> impl Iterator<Item = &HexLine> {
         self.lines.iter()
     }
+
+    pub fn clear(&mut self) {
+        self.lines.clear();
+    }
+
+    pub fn set_limit(&mut self, limit: usize) {
+        self.lines.set_limit(limit);
+    }
+}
+
+pub struct PlotSeries {
+    pub name: String,
+    points: VecDeque<[f64; 2]>,
+    next_x: f64,
+}
+
+impl PlotSeries {
+    fn new(name: String) -> Self {
+        Self {
+            name,
+            points: VecDeque::new(),
+            next_x: 0.0,
+        }
+    }
+
+    fn push_samples(&mut self, samples: &[f64], limit: usize) {
+        for sample in samples {
+            if !sample.is_finite() {
+                continue;
+            }
+            self.points.push_back([self.next_x, *sample]);
+            self.next_x += 1.0;
+        }
+        while self.points.len() > limit {
+            self.points.pop_front();
+        }
+    }
+
+    pub fn points(&self) -> impl Iterator<Item = [f64; 2]> + '_ {
+        self.points.iter().copied()
+    }
+
+    pub fn render_points_time_series(&self, x_min: f64, x_max: f64, max_points: usize) -> Vec<[f64; 2]> {
+        if self.points.is_empty() || max_points == 0 {
+            return Vec::new();
+        }
+
+        let visible: Vec<[f64; 2]> = self
+            .points
+            .iter()
+            .copied()
+            .filter(|point| point[0] >= x_min && point[0] <= x_max)
+            .collect();
+        if visible.len() <= max_points {
+            return visible;
+        }
+
+        let bucket_count = (max_points / 2).max(1);
+        let width = (x_max - x_min).max(1.0);
+        let bucket_width = width / bucket_count as f64;
+        let mut rendered = Vec::with_capacity(bucket_count * 2);
+        let mut start = 0usize;
+
+        for bucket_index in 0..bucket_count {
+            let bucket_start = x_min + bucket_width * bucket_index as f64;
+            let bucket_end = if bucket_index + 1 == bucket_count {
+                x_max
+            } else {
+                bucket_start + bucket_width
+            };
+
+            let mut min_point: Option<[f64; 2]> = None;
+            let mut max_point: Option<[f64; 2]> = None;
+
+            while start < visible.len() {
+                let point = visible[start];
+                if point[0] > bucket_end {
+                    break;
+                }
+                if point[0] >= bucket_start {
+                    match min_point {
+                        Some(current) if current[1] <= point[1] => {}
+                        _ => min_point = Some(point),
+                    }
+                    match max_point {
+                        Some(current) if current[1] >= point[1] => {}
+                        _ => max_point = Some(point),
+                    }
+                }
+                start += 1;
+            }
+
+            match (min_point, max_point) {
+                (Some(a), Some(b)) if a[0] <= b[0] => {
+                    rendered.push(a);
+                    if a != b {
+                        rendered.push(b);
+                    }
+                }
+                (Some(a), Some(b)) => {
+                    rendered.push(b);
+                    if a != b {
+                        rendered.push(a);
+                    }
+                }
+                (Some(a), None) | (None, Some(a)) => rendered.push(a),
+                (None, None) => {}
+            }
+        }
+
+        if rendered.len() > max_points {
+            let stride = rendered.len().div_ceil(max_points);
+            rendered.into_iter().step_by(stride).collect()
+        } else {
+            rendered
+        }
+    }
+
+    pub fn render_points_xy(&self, max_points: usize) -> Vec<[f64; 2]> {
+        if self.points.is_empty() || max_points == 0 {
+            return Vec::new();
+        }
+        if self.points.len() <= max_points {
+            return self.points.iter().copied().collect();
+        }
+
+        let stride = self.points.len().div_ceil(max_points);
+        self.points.iter().copied().step_by(stride).collect()
+    }
+}
+
+pub enum PlotSeriesKind {
+    TimeSeries,
+    XY,
+}
+
+pub struct PlotBuffer {
+    limit: usize,
+    kind: PlotSeriesKind,
+    series: Vec<PlotSeries>,
+}
+
+impl PlotBuffer {
+    pub fn new(limit: usize) -> Self {
+        Self {
+            limit,
+            kind: PlotSeriesKind::TimeSeries,
+            series: Vec::new(),
+        }
+    }
+
+    pub fn push(&mut self, entry: &DecodedEntry) {
+        if let DecodedData::Plot(frame) = &entry.data {
+            self.push_frame(&entry.pipeline_name, frame);
+        }
+    }
+
+    fn push_frame(&mut self, pipeline_name: &str, frame: &PlotFrame) {
+        self.kind = match frame.format {
+            PlotFormat::XY => PlotSeriesKind::XY,
+            PlotFormat::Interleaved | PlotFormat::Block => PlotSeriesKind::TimeSeries,
+        };
+
+        if matches!(frame.format, PlotFormat::XY) {
+            self.push_xy_frame(pipeline_name, frame);
+            return;
+        }
+
+        for (index, channel) in frame.channels.iter().enumerate() {
+            let series_name = if frame.channels.len() == 1 {
+                pipeline_name.to_owned()
+            } else {
+                format!("{pipeline_name}:ch{}", index + 1)
+            };
+
+            if let Some(series) = self
+                .series
+                .iter_mut()
+                .find(|series| series.name == series_name)
+            {
+                series.push_samples(channel, self.limit);
+            } else {
+                let mut series = PlotSeries::new(series_name);
+                series.push_samples(channel, self.limit);
+                self.series.push(series);
+            }
+        }
+    }
+
+    fn push_xy_frame(&mut self, pipeline_name: &str, frame: &PlotFrame) {
+        if frame.channels.len() < 2 {
+            return;
+        }
+
+        let x = &frame.channels[0];
+        let y = &frame.channels[1];
+        let len = x.len().min(y.len());
+        let series_name = format!("{pipeline_name}:xy");
+
+        let series = if let Some(series) = self
+            .series
+            .iter_mut()
+            .find(|series| series.name == series_name)
+        {
+            series
+        } else {
+            self.series.push(PlotSeries::new(series_name));
+            self.series.last_mut().expect("just pushed")
+        };
+
+        for index in 0..len {
+            if !x[index].is_finite() || !y[index].is_finite() {
+                continue;
+            }
+            series.points.push_back([x[index], y[index]]);
+        }
+        while series.points.len() > self.limit {
+            series.points.pop_front();
+        }
+    }
+
+    pub fn clear(&mut self) {
+        self.series.clear();
+    }
+
+    pub fn set_limit(&mut self, limit: usize) {
+        self.limit = limit;
+        for series in &mut self.series {
+            while series.points.len() > self.limit {
+                series.points.pop_front();
+            }
+        }
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.series.is_empty()
+    }
+
+    pub fn kind(&self) -> &PlotSeriesKind {
+        &self.kind
+    }
+
+    pub fn iter(&self) -> impl Iterator<Item = &PlotSeries> {
+        self.series.iter()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use xserial_client::event::DecodedEntry;
+    use xserial_core::protocol::DecodedData;
+    use xserial_core::protocol::plot::{PlotFrame, SampleType};
+
+    fn plot_entry() -> DecodedEntry {
+        DecodedEntry {
+            pipeline_name: String::from("plot"),
+            data: DecodedData::Plot(PlotFrame {
+                channels: vec![vec![1.0, 2.0, 3.0], vec![10.0, 20.0, 30.0]],
+                raw: vec![],
+                sample_type: SampleType::F32,
+                format: PlotFormat::Interleaved,
+            }),
+        }
+    }
+
+    fn xy_plot_entry() -> DecodedEntry {
+        DecodedEntry {
+            pipeline_name: String::from("xy"),
+            data: DecodedData::Plot(PlotFrame {
+                channels: vec![vec![0.0, 1.0, 2.0], vec![10.0, 20.0, 30.0]],
+                raw: vec![],
+                sample_type: SampleType::F32,
+                format: PlotFormat::XY,
+            }),
+        }
+    }
+
+    #[test]
+    fn plot_buffer_creates_series_per_channel() {
+        let mut buffer = PlotBuffer::new(8);
+        buffer.push(&plot_entry());
+
+        let series: Vec<_> = buffer.iter().collect();
+        assert_eq!(series.len(), 2);
+        assert_eq!(series[0].name, "plot:ch1");
+        assert_eq!(series[1].name, "plot:ch2");
+        assert_eq!(series[0].points().count(), 3);
+        assert_eq!(series[1].points().count(), 3);
+    }
+
+    #[test]
+    fn plot_buffer_limit_and_clear_work() {
+        let mut buffer = PlotBuffer::new(2);
+        buffer.push(&plot_entry());
+        assert_eq!(buffer.iter().next().unwrap().points().count(), 2);
+
+        buffer.clear();
+        assert!(buffer.is_empty());
+    }
+
+    #[test]
+    fn plot_buffer_xy_uses_xy_points() {
+        let mut buffer = PlotBuffer::new(8);
+        buffer.push(&xy_plot_entry());
+
+        assert!(matches!(buffer.kind(), PlotSeriesKind::XY));
+        let series: Vec<_> = buffer.iter().collect();
+        assert_eq!(series.len(), 1);
+        let points: Vec<_> = series[0].points().collect();
+        assert_eq!(points, vec![[0.0, 10.0], [1.0, 20.0], [2.0, 30.0]]);
+    }
+
+    #[test]
+    fn plot_series_time_series_downsamples_to_budget() {
+        let mut series = PlotSeries::new(String::from("plot"));
+        series.push_samples(&(0..100).map(|n| n as f64).collect::<Vec<_>>(), 200);
+
+        let rendered = series.render_points_time_series(0.0, 99.0, 16);
+        assert!(!rendered.is_empty());
+        assert!(rendered.len() <= 16);
+        assert!(rendered.iter().all(|point| point[0] >= 0.0 && point[0] <= 99.0));
+    }
+
+    #[test]
+    fn plot_series_xy_downsamples_to_budget() {
+        let mut series = PlotSeries::new(String::from("xy"));
+        for n in 0..100 {
+            series.points.push_back([n as f64, (n * 2) as f64]);
+        }
+
+        let rendered = series.render_points_xy(10);
+        assert!(rendered.len() <= 10);
+        assert_eq!(rendered.first().copied(), Some([0.0, 0.0]));
+    }
 }
diff --git a/crates/xserial-gui/src/panels/config.rs b/crates/xserial-gui/src/panels/config.rs
index d882c6d..4960078 100644
--- a/crates/xserial-gui/src/panels/config.rs
+++ b/crates/xserial-gui/src/panels/config.rs
@@ -1,6 +1,10 @@
 use egui::{ComboBox, DragValue, ScrollArea, TextEdit, Ui};
 use xserial_client::config::{DecoderConfig, FramerConfig, PipelineConfig, SessionConfig};
+use xserial_core::protocol::plot::PlotFormat;
 use xserial_core::transport::TransportConfig;
+use xserial_core::transport::serial::{
+    SerialDataBits, SerialFlowControl, SerialParity, SerialStopBits,
+};
 
 // ── 表单数据结构（简化版，方便 UI 渲染）────────────────────────────
 
@@ -9,14 +13,27 @@ pub struct ConfigForm {
     pub transport: TransportChoice,
     pub port: String,
     pub baud: u32,
+    pub serial_data_bits: SerialDataBits,
+    pub serial_parity: SerialParity,
+    pub serial_stop_bits: SerialStopBits,
+    pub serial_flow_control: SerialFlowControl,
     pub addr: String,
     pub udp_bind: String,
     pub udp_remote: String,
-    pub pipelines: Vec<(String, FramerChoice, DecoderChoice)>,
+    pub pipelines: Vec<PipelineForm>,
     pub history: usize,
     pub auto_reconnect: bool,
 }
 
+#[derive(Clone)]
+pub struct PipelineForm {
+    pub name: String,
+    pub framer: FramerChoice,
+    pub decoder: DecoderChoice,
+    pub plot_channels: usize,
+    pub plot_format: PlotFormat,
+}
+
 #[derive(Clone, PartialEq)]
 pub enum TransportChoice {
     Serial,
@@ -28,6 +45,7 @@ pub enum TransportChoice {
 pub enum FramerChoice {
     Line,
     Fixed(usize),
+    MixedTextPlot,
 }
 
 #[derive(Clone, PartialEq)]
@@ -35,6 +53,7 @@ pub enum DecoderChoice {
     Text,
     Hex,
     Plot,
+    MixedTextPlot,
 }
 
 impl Default for ConfigForm {
@@ -43,10 +62,20 @@ impl Default for ConfigForm {
             transport: TransportChoice::Tcp,
             port: "/dev/ttyUSB0".into(),
             baud: 115200,
+            serial_data_bits: SerialDataBits::Eight,
+            serial_parity: SerialParity::None,
+            serial_stop_bits: SerialStopBits::One,
+            serial_flow_control: SerialFlowControl::None,
             addr: "127.0.0.1:8080".into(),
             udp_bind: "0.0.0.0:9000".into(),
             udp_remote: String::new(),
-            pipelines: vec![("text".into(), FramerChoice::Line, DecoderChoice::Text)],
+            pipelines: vec![PipelineForm {
+                name: "text".into(),
+                framer: FramerChoice::Line,
+                decoder: DecoderChoice::Text,
+                plot_channels: 1,
+                plot_format: PlotFormat::Interleaved,
+            }],
             history: 10000,
             auto_reconnect: false,
         }
@@ -69,6 +98,22 @@ impl ConfigForm {
                 TransportConfig::Serial { baud_rate, .. } => *baud_rate,
                 _ => 115200,
             },
+            serial_data_bits: match &config.transport {
+                TransportConfig::Serial { data_bits, .. } => *data_bits,
+                _ => SerialDataBits::Eight,
+            },
+            serial_parity: match &config.transport {
+                TransportConfig::Serial { parity, .. } => *parity,
+                _ => SerialParity::None,
+            },
+            serial_stop_bits: match &config.transport {
+                TransportConfig::Serial { stop_bits, .. } => *stop_bits,
+                _ => SerialStopBits::One,
+            },
+            serial_flow_control: match &config.transport {
+                TransportConfig::Serial { flow_control, .. } => *flow_control,
+                _ => SerialFlowControl::None,
+            },
             addr: match &config.transport {
                 TransportConfig::Tcp { addr } => addr.clone(),
                 _ => String::from("127.0.0.1:8080"),
@@ -88,6 +133,7 @@ impl ConfigForm {
                     let framer = match &pipeline.framer {
                         FramerConfig::Line { .. } => FramerChoice::Line,
                         FramerConfig::Fixed { frame_len } => FramerChoice::Fixed(*frame_len),
+                        FramerConfig::MixedTextPlot { .. } => FramerChoice::MixedTextPlot,
                         FramerConfig::Length { .. } | FramerConfig::Cobs { .. } => {
                             FramerChoice::Line
                         }
@@ -96,8 +142,23 @@ impl ConfigForm {
                         DecoderConfig::Text { .. } => DecoderChoice::Text,
                         DecoderConfig::Hex { .. } => DecoderChoice::Hex,
                         DecoderConfig::Plot { .. } => DecoderChoice::Plot,
+                        DecoderConfig::MixedTextPlot { .. } => DecoderChoice::MixedTextPlot,
                     };
-                    (pipeline.name.clone(), framer, decoder)
+                    let plot_channels = match &pipeline.decoder {
+                        DecoderConfig::Plot { channels, .. } => *channels,
+                        _ => 1,
+                    };
+                    let plot_format = match &pipeline.decoder {
+                        DecoderConfig::Plot { format, .. } => *format,
+                        _ => PlotFormat::Interleaved,
+                    };
+                    PipelineForm {
+                        name: pipeline.name.clone(),
+                        framer,
+                        decoder,
+                        plot_channels,
+                        plot_format,
+                    }
                 })
                 .collect(),
             history: config.history_limit,
@@ -112,6 +173,10 @@ impl ConfigForm {
                 TransportChoice::Serial => TransportConfig::Serial {
                     port: self.port.clone(),
                     baud_rate: self.baud,
+                    data_bits: self.serial_data_bits,
+                    parity: self.serial_parity,
+                    stop_bits: self.serial_stop_bits,
+                    flow_control: self.serial_flow_control,
                 },
                 TransportChoice::Tcp => TransportConfig::Tcp {
                     addr: self.addr.clone(),
@@ -128,16 +193,21 @@ impl ConfigForm {
             pipelines: self
                 .pipelines
                 .iter()
-                .map(|(name, fc, dc)| PipelineConfig {
-                    name: name.clone(),
-                    framer: match fc {
+                .map(|pipeline| PipelineConfig {
+                    name: pipeline.name.clone(),
+                    framer: match &pipeline.framer {
                         FramerChoice::Line => FramerConfig::Line {
                             strip_cr: true,
                             max_line_len: 1_048_576,
                         },
                         FramerChoice::Fixed(n) => FramerConfig::Fixed { frame_len: *n },
+                        FramerChoice::MixedTextPlot => FramerConfig::MixedTextPlot {
+                            strip_cr: true,
+                            max_line_len: 1_048_576,
+                            max_plot_frame: 1_048_576,
+                        },
                     },
-                    decoder: match dc {
+                    decoder: match &pipeline.decoder {
                         DecoderChoice::Text => DecoderConfig::Text {
                             encoding: xserial_core::protocol::text::TextEncoding::Utf8,
                         },
@@ -150,8 +220,11 @@ impl ConfigForm {
                         DecoderChoice::Plot => DecoderConfig::Plot {
                             sample_type: xserial_core::protocol::plot::SampleType::F32,
                             endian: xserial_core::protocol::Endian::Little,
-                            channels: 1,
-                            format: xserial_core::protocol::plot::PlotFormat::Interleaved,
+                            channels: pipeline.plot_channels.max(1),
+                            format: pipeline.plot_format,
+                        },
+                        DecoderChoice::MixedTextPlot => DecoderConfig::MixedTextPlot {
+                            encoding: xserial_core::protocol::text::TextEncoding::Utf8,
                         },
                     },
                 })
@@ -166,6 +239,7 @@ impl ConfigForm {
 
 pub fn render(ui: &mut Ui, form: &mut ConfigForm, submit_label: &str) -> Option<SessionConfig> {
     let mut result = None;
+    let mut validation_errors = Vec::new();
 
     ScrollArea::vertical().show(ui, |ui| {
         ui.heading("Transport");
@@ -194,6 +268,106 @@ pub fn render(ui: &mut Ui, form: &mut ConfigForm, submit_label: &str) -> Option<
                     ui.label("Baud:");
                     ui.add(DragValue::new(&mut form.baud).range(300..=12_000_000));
                 });
+                ui.horizontal(|ui| {
+                    ui.label("Data bits:");
+                    ComboBox::from_id_salt("serial_data_bits")
+                        .selected_text(match form.serial_data_bits {
+                            SerialDataBits::Five => "5",
+                            SerialDataBits::Six => "6",
+                            SerialDataBits::Seven => "7",
+                            SerialDataBits::Eight => "8",
+                        })
+                        .show_ui(ui, |ui| {
+                            ui.selectable_value(
+                                &mut form.serial_data_bits,
+                                SerialDataBits::Five,
+                                "5",
+                            );
+                            ui.selectable_value(
+                                &mut form.serial_data_bits,
+                                SerialDataBits::Six,
+                                "6",
+                            );
+                            ui.selectable_value(
+                                &mut form.serial_data_bits,
+                                SerialDataBits::Seven,
+                                "7",
+                            );
+                            ui.selectable_value(
+                                &mut form.serial_data_bits,
+                                SerialDataBits::Eight,
+                                "8",
+                            );
+                        });
+                });
+                ui.horizontal(|ui| {
+                    ui.label("Parity:");
+                    ComboBox::from_id_salt("serial_parity")
+                        .selected_text(match form.serial_parity {
+                            SerialParity::None => "None",
+                            SerialParity::Odd => "Odd",
+                            SerialParity::Even => "Even",
+                        })
+                        .show_ui(ui, |ui| {
+                            ui.selectable_value(
+                                &mut form.serial_parity,
+                                SerialParity::None,
+                                "None",
+                            );
+                            ui.selectable_value(&mut form.serial_parity, SerialParity::Odd, "Odd");
+                            ui.selectable_value(
+                                &mut form.serial_parity,
+                                SerialParity::Even,
+                                "Even",
+                            );
+                        });
+                });
+                ui.horizontal(|ui| {
+                    ui.label("Stop bits:");
+                    ComboBox::from_id_salt("serial_stop_bits")
+                        .selected_text(match form.serial_stop_bits {
+                            SerialStopBits::One => "1",
+                            SerialStopBits::Two => "2",
+                        })
+                        .show_ui(ui, |ui| {
+                            ui.selectable_value(
+                                &mut form.serial_stop_bits,
+                                SerialStopBits::One,
+                                "1",
+                            );
+                            ui.selectable_value(
+                                &mut form.serial_stop_bits,
+                                SerialStopBits::Two,
+                                "2",
+                            );
+                        });
+                });
+                ui.horizontal(|ui| {
+                    ui.label("Flow:");
+                    ComboBox::from_id_salt("serial_flow_control")
+                        .selected_text(match form.serial_flow_control {
+                            SerialFlowControl::None => "None",
+                            SerialFlowControl::Software => "Software",
+                            SerialFlowControl::Hardware => "Hardware",
+                        })
+                        .show_ui(ui, |ui| {
+                            ui.selectable_value(
+                                &mut form.serial_flow_control,
+                                SerialFlowControl::None,
+                                "None",
+                            );
+                            ui.selectable_value(
+                                &mut form.serial_flow_control,
+                                SerialFlowControl::Software,
+                                "Software",
+                            );
+                            ui.selectable_value(
+                                &mut form.serial_flow_control,
+                                SerialFlowControl::Hardware,
+                                "Hardware",
+                            );
+                        });
+                });
             }
             TransportChoice::Tcp => {
                 ui.horizontal(|ui| {
@@ -219,47 +393,60 @@ pub fn render(ui: &mut Ui, form: &mut ConfigForm, submit_label: &str) -> Option<
         let mut remove = None;
 
         // 管道列表
-        for (i, (name, fc, dc)) in form.pipelines.iter_mut().enumerate() {
+        for (i, pipeline) in form.pipelines.iter_mut().enumerate() {
             ui.group(|ui| {
                 ui.horizontal(|ui| {
                     ui.label("Name:");
-                    ui.add(TextEdit::singleline(name).desired_width(60.0));
+                    ui.add(TextEdit::singleline(&mut pipeline.name).desired_width(60.0));
 
                     // Framer 选择
-                    let fsel = match fc {
+                    let fsel = match &pipeline.framer {
                         FramerChoice::Line => "Line".to_string(),
                         FramerChoice::Fixed(n) => format!("Fixed({})", n),
+                        FramerChoice::MixedTextPlot => "MixedTextPlot".to_string(),
                     };
                     ComboBox::from_id_salt(format!("f{}", i))
                         .selected_text(fsel)
                         .show_ui(ui, |ui| {
                             if ui.selectable_label(false, "Line").clicked() {
-                                *fc = FramerChoice::Line;
+                                pipeline.framer = FramerChoice::Line;
                             }
                             if ui.selectable_label(false, "Fixed").clicked() {
-                                *fc = FramerChoice::Fixed(8);
+                                pipeline.framer = FramerChoice::Fixed(8);
+                            }
+                            if ui.selectable_label(false, "MixedTextPlot").clicked() {
+                                pipeline.framer = FramerChoice::MixedTextPlot;
+                                pipeline.decoder = DecoderChoice::MixedTextPlot;
                             }
                         });
-                    if let FramerChoice::Fixed(n) = fc {
+                    if let FramerChoice::Fixed(n) = &mut pipeline.framer {
                         ui.add(DragValue::new(n).range(1..=65536));
                     }
 
                     // Decoder 选择
                     ComboBox::from_id_salt(format!("d{}", i))
-                        .selected_text(match dc {
+                        .selected_text(match pipeline.decoder {
                             DecoderChoice::Text => "Text",
                             DecoderChoice::Hex => "Hex",
                             DecoderChoice::Plot => "Plot",
+                            DecoderChoice::MixedTextPlot => "MixedTextPlot",
                         })
                         .show_ui(ui, |ui| {
                             if ui.selectable_label(false, "Text").clicked() {
-                                *dc = DecoderChoice::Text;
+                                pipeline.decoder = DecoderChoice::Text;
                             }
                             if ui.selectable_label(false, "Hex").clicked() {
-                                *dc = DecoderChoice::Hex;
+                                pipeline.decoder = DecoderChoice::Hex;
                             }
                             if ui.selectable_label(false, "Plot").clicked() {
-                                *dc = DecoderChoice::Plot;
+                                if matches!(pipeline.framer, FramerChoice::Line) {
+                                    pipeline.framer = FramerChoice::Fixed(256);
+                                }
+                                pipeline.decoder = DecoderChoice::Plot;
+                            }
+                            if ui.selectable_label(false, "MixedTextPlot").clicked() {
+                                pipeline.framer = FramerChoice::MixedTextPlot;
+                                pipeline.decoder = DecoderChoice::MixedTextPlot;
                             }
                         });
 
@@ -267,6 +454,88 @@ pub fn render(ui: &mut Ui, form: &mut ConfigForm, submit_label: &str) -> Option<
                         remove = Some(i);
                     }
                 });
+
+                if matches!(pipeline.decoder, DecoderChoice::Plot) {
+                    ui.horizontal(|ui| {
+                        ui.label("Plot channels:");
+                        ui.add(DragValue::new(&mut pipeline.plot_channels).range(1..=32));
+                    });
+                    ui.horizontal(|ui| {
+                        ui.label("Plot format:");
+                        ComboBox::from_id_salt(format!("plot_format{}", i))
+                            .selected_text(match pipeline.plot_format {
+                                PlotFormat::Interleaved => "Interleaved",
+                                PlotFormat::Block => "Block",
+                                PlotFormat::XY => "XY",
+                            })
+                            .show_ui(ui, |ui| {
+                                ui.selectable_value(
+                                    &mut pipeline.plot_format,
+                                    PlotFormat::Interleaved,
+                                    "Interleaved",
+                                );
+                                ui.selectable_value(
+                                    &mut pipeline.plot_format,
+                                    PlotFormat::Block,
+                                    "Block",
+                                );
+                                ui.selectable_value(
+                                    &mut pipeline.plot_format,
+                                    PlotFormat::XY,
+                                    "XY",
+                                );
+                            });
+                    });
+
+                    if matches!(pipeline.plot_format, PlotFormat::XY) {
+                        pipeline.plot_channels = 2;
+                    }
+
+                    match &pipeline.framer {
+                        FramerChoice::Line => {
+                            let message = "Plot decoder requires Fixed framer for raw binary samples";
+                            ui.colored_label(egui::Color32::RED, message);
+                            validation_errors
+                                .push(format!("pipeline '{}': {message}", pipeline.name));
+                        }
+                        FramerChoice::Fixed(n)
+                            if *n % (pipeline.plot_channels.max(1) * 4) != 0 =>
+                        {
+                            let message = format!(
+                                "Plot decoder currently expects interleaved f32 data, so frame length must be a multiple of {} bytes",
+                                pipeline.plot_channels.max(1) * 4
+                            );
+                            ui.colored_label(egui::Color32::RED, &message);
+                            validation_errors
+                                .push(format!("pipeline '{}': {message}", pipeline.name));
+                        }
+                        FramerChoice::MixedTextPlot => {
+                            let message = "Raw Plot decoder cannot be used with MixedTextPlot framer";
+                            ui.colored_label(egui::Color32::RED, message);
+                            validation_errors
+                                .push(format!("pipeline '{}': {message}", pipeline.name));
+                        }
+                        FramerChoice::Fixed(_) => {}
+                    }
+
+                    if matches!(pipeline.plot_format, PlotFormat::XY) && pipeline.plot_channels != 2
+                    {
+                        let message = "XY plot requires exactly 2 channels";
+                        ui.colored_label(egui::Color32::RED, message);
+                        validation_errors.push(format!(
+                            "pipeline '{}': {message}",
+                            pipeline.name
+                        ));
+                    }
+                }
+
+                if matches!(pipeline.decoder, DecoderChoice::MixedTextPlot)
+                    && !matches!(pipeline.framer, FramerChoice::MixedTextPlot)
+                {
+                    let message = "MixedTextPlot decoder requires MixedTextPlot framer";
+                    ui.colored_label(egui::Color32::RED, message);
+                    validation_errors.push(format!("pipeline '{}': {message}", pipeline.name));
+                }
             });
         }
 
@@ -275,11 +544,13 @@ pub fn render(ui: &mut Ui, form: &mut ConfigForm, submit_label: &str) -> Option<
         }
 
         if ui.button("+ Add Pipeline").clicked() {
-            form.pipelines.push((
-                format!("p{}", form.pipelines.len()),
-                FramerChoice::Line,
-                DecoderChoice::Text,
-            ));
+            form.pipelines.push(PipelineForm {
+                name: format!("p{}", form.pipelines.len()),
+                framer: FramerChoice::Line,
+                decoder: DecoderChoice::Text,
+                plot_channels: 1,
+                plot_format: PlotFormat::Interleaved,
+            });
         }
 
         ui.separator();
@@ -290,8 +561,13 @@ pub fn render(ui: &mut Ui, form: &mut ConfigForm, submit_label: &str) -> Option<
         ui.checkbox(&mut form.auto_reconnect, "Auto reconnect");
 
         ui.separator();
+        for error in &validation_errors {
+            ui.colored_label(egui::Color32::RED, error);
+        }
         if ui.button(submit_label).clicked() {
-            result = Some(form.to_session_config());
+            if validation_errors.is_empty() {
+                result = Some(form.to_session_config());
+            }
         }
     });
 
diff --git a/crates/xserial-gui/src/panels/mod.rs b/crates/xserial-gui/src/panels/mod.rs
index 38cf6a1..1d0c696 100644
--- a/crates/xserial-gui/src/panels/mod.rs
+++ b/crates/xserial-gui/src/panels/mod.rs
@@ -1,4 +1,5 @@
 pub mod config;
 pub mod console;
 pub mod hex_view;
+pub mod plot_view;
 pub mod sidebar;
diff --git a/crates/xserial-gui/src/panels/plot_view.rs b/crates/xserial-gui/src/panels/plot_view.rs
new file mode 100644
index 0000000..9ea070d
--- /dev/null
+++ b/crates/xserial-gui/src/panels/plot_view.rs
@@ -0,0 +1,199 @@
+use crate::buffers::{PlotBuffer, PlotSeriesKind};
+use egui::{Button, Ui, vec2};
+use egui_plot::{Legend, Line, Plot, PlotBounds, PlotPoints};
+
+pub struct PlotViewState {
+    pub lock_x: bool,
+    pub lock_y: bool,
+    pub box_zoom: bool,
+    pub follow_latest: bool,
+    pub last_bounds: Option<PlotBounds>,
+}
+
+impl Default for PlotViewState {
+    fn default() -> Self {
+        Self {
+            lock_x: false,
+            lock_y: false,
+            box_zoom: false,
+            follow_latest: false,
+            last_bounds: None,
+        }
+    }
+}
+
+pub fn render(ui: &mut Ui, buf: &PlotBuffer, session_id: u64, state: &mut PlotViewState) {
+    if buf.is_empty() {
+        ui.label("no plot data");
+        return;
+    }
+
+    let mut auto_fit = false;
+    let mut reset_view = false;
+    let mut zoom_x = 1.0_f32;
+    let mut zoom_y = 1.0_f32;
+
+    ui.horizontal_wrapped(|ui| {
+        if ui.button("Auto Fit").clicked() {
+            auto_fit = true;
+        }
+        if ui.button("Reset View").clicked() {
+            reset_view = true;
+        }
+        ui.separator();
+        ui.checkbox(&mut state.lock_x, "Lock X");
+        ui.checkbox(&mut state.lock_y, "Lock Y");
+        ui.checkbox(&mut state.box_zoom, "Box Zoom");
+        if matches!(buf.kind(), PlotSeriesKind::TimeSeries) {
+            ui.checkbox(&mut state.follow_latest, "Follow Latest");
+        } else {
+            state.follow_latest = false;
+        }
+        ui.separator();
+        if ui
+            .add_enabled(!state.lock_x, Button::new("X-"))
+            .on_hover_text("Zoom out X axis")
+            .clicked()
+        {
+            zoom_x = 0.8;
+        }
+        if ui
+            .add_enabled(!state.lock_x, Button::new("X+"))
+            .on_hover_text("Zoom in X axis")
+            .clicked()
+        {
+            zoom_x = 1.25;
+        }
+        if ui
+            .add_enabled(!state.lock_y, Button::new("Y-"))
+            .on_hover_text("Zoom out Y axis")
+            .clicked()
+        {
+            zoom_y = 0.8;
+        }
+        if ui
+            .add_enabled(!state.lock_y, Button::new("Y+"))
+            .on_hover_text("Zoom in Y axis")
+            .clicked()
+        {
+            zoom_y = 1.25;
+        }
+    });
+
+    if let Some(bounds) = state.last_bounds {
+        ui.horizontal_wrapped(|ui| {
+            ui.monospace(format!(
+                "X [{:.3}, {:.3}]  Y [{:.3}, {:.3}]",
+                bounds.min()[0],
+                bounds.max()[0],
+                bounds.min()[1],
+                bounds.max()[1],
+            ));
+        });
+    }
+
+    let data_bounds = plot_bounds(buf);
+    let mut plot = Plot::new(format!("plot_view_{session_id}"))
+        .legend(Legend::default())
+        .allow_boxed_zoom(state.box_zoom)
+        .allow_zoom([!state.lock_x, !state.lock_y])
+        .allow_drag([!state.lock_x, !state.lock_y])
+        .allow_axis_zoom_drag([!state.lock_x, !state.lock_y])
+        .allow_scroll([
+            !state.lock_x && matches!(buf.kind(), PlotSeriesKind::TimeSeries),
+            !state.lock_y && matches!(buf.kind(), PlotSeriesKind::TimeSeries),
+        ]);
+    if reset_view {
+        plot = plot.reset();
+    }
+
+    plot.show(ui, |plot_ui| {
+        let current_bounds = plot_ui.plot_bounds();
+        state.last_bounds = current_bounds.is_finite().then_some(current_bounds);
+        let pixel_width = plot_ui.response().rect.width().max(64.0);
+        let max_render_points = (pixel_width as usize).saturating_mul(2);
+
+        if auto_fit {
+            if let Some(bounds) = data_bounds {
+                plot_ui.set_auto_bounds(false);
+                plot_ui.set_plot_bounds(bounds);
+                state.last_bounds = Some(bounds);
+            }
+        } else if state.follow_latest && matches!(buf.kind(), PlotSeriesKind::TimeSeries) {
+            if let Some(bounds) = data_bounds {
+                let current_width = current_bounds.width();
+                let data_width = bounds.width();
+                let x_range = if current_width.is_finite() && current_width > 0.0 && data_width > current_width {
+                    (bounds.max()[0] - current_width)..=bounds.max()[0]
+                } else {
+                    bounds.min()[0]..=bounds.max()[0]
+                };
+                plot_ui.set_auto_bounds([false, plot_ui.auto_bounds().y]);
+                plot_ui.set_plot_bounds_x(x_range.clone());
+
+                let mut followed = current_bounds;
+                followed.set_x(&PlotBounds::from_min_max([*x_range.start(), current_bounds.min()[1]], [*x_range.end(), current_bounds.max()[1]]));
+                state.last_bounds = Some(followed);
+            }
+        } else if zoom_x != 1.0 || zoom_y != 1.0 {
+            let center = plot_ui.plot_bounds().center();
+            plot_ui.zoom_bounds(vec2(zoom_x, zoom_y), center);
+        }
+
+        if let Some(bounds) = data_bounds {
+            if !bounds.is_valid_x() {
+                plot_ui.set_auto_bounds([true, plot_ui.auto_bounds().y]);
+            }
+            if !bounds.is_valid_y() {
+                plot_ui.set_auto_bounds([plot_ui.auto_bounds().x, true]);
+            }
+        }
+
+        for series in buf.iter() {
+            let sampled_points = match buf.kind() {
+                PlotSeriesKind::TimeSeries => {
+                    series.render_points_time_series(
+                        current_bounds.min()[0],
+                        current_bounds.max()[0],
+                        max_render_points,
+                    )
+                }
+                PlotSeriesKind::XY => series.render_points_xy(max_render_points),
+            };
+            let points = PlotPoints::from_iter(sampled_points);
+            plot_ui.line(Line::new(series.name.clone(), points));
+        }
+    });
+}
+
+fn plot_bounds(buf: &PlotBuffer) -> Option<PlotBounds> {
+    let mut bounds = PlotBounds::NOTHING;
+
+    for series in buf.iter() {
+        for [x, y] in series.points() {
+            if x.is_finite() && y.is_finite() {
+                bounds.extend_with(&[x, y].into());
+            }
+        }
+    }
+
+    if !bounds.is_finite() {
+        return None;
+    }
+
+    if bounds.width() <= 0.0 {
+        let center_x = bounds.center().x;
+        bounds.set_x_center_width(center_x, 1.0);
+    } else {
+        bounds.expand_x(bounds.width() * 0.05);
+    }
+
+    if bounds.height() <= 0.0 {
+        let center_y = bounds.center().y;
+        bounds.set_y_center_height(center_y, 1.0);
+    } else {
+        bounds.expand_y(bounds.height() * 0.1);
+    }
+
+    Some(bounds)
+}
diff --git a/tools/gen_plot.py b/tools/gen_plot.py
deleted file mode 100755
index 6553978..0000000
--- a/tools/gen_plot.py
+++ /dev/null
@@ -1,112 +0,0 @@
-#!/usr/bin/env python3
-"""
-SerialPlot 协议测试数据生成器
-
-协议格式:
-  [Sync: AA 55] [Size: 2B LE] [Payload: N×2B i16 LE] [Checksum: 1B LSB sum of payload]
-
-用法:
-  python3 gen_plot.py /dev/pts/X --channels 2 --wave sine
-  python3 gen_plot.py /dev/pts/X --channels 2 --wave sine --freq 0.3  # 慢波，易观察
-  python3 gen_plot.py /dev/pts/X --channels 3 --wave saw --freq 0.2
-"""
-import struct
-import sys
-import time
-import math
-import argparse
-
-
-def checksum(data: bytes) -> int:
-    return sum(data) & 0xFF
-
-
-def make_frame(channel_data: list[list[int]]) -> bytes:
-    num_channels = len(channel_data)
-    num_samples = len(channel_data[0])
-    payload = bytearray()
-    for i in range(num_samples):
-        for ch in range(num_channels):
-            payload.extend(struct.pack('<h', channel_data[ch][i]))
-
-    frame = bytearray([0xAA, 0x55])
-    frame.append(len(payload) & 0xFF)
-    frame.append((len(payload) >> 8) & 0xFF)
-    frame.extend(payload)
-    frame.append(checksum(payload))
-    return bytes(frame)
-
-
-def generate_wave(
-    num_channels: int,
-    num_samples: int,
-    wave_type: str,
-    freq: float,
-    amplitude: int,
-) -> list[list[int]]:
-    channels = []
-    for ch in range(num_channels):
-        phase_offset = ch * (2 * math.pi / num_channels)
-        samples = []
-        for i in range(num_samples):
-            t = i / num_samples
-            if wave_type == 'sine':
-                angle = 2 * math.pi * t * freq + phase_offset
-                value = math.sin(angle)
-            elif wave_type == 'saw':
-                value = 2 * ((t * freq) % 1.0) - 1.0
-            elif wave_type == 'square':
-                value = 1.0 if ((t * freq) % 2.0) < 1.0 else -1.0
-            else:
-                value = 0.0
-            samples.append(int(value * amplitude))
-        channels.append(samples)
-    return channels
-
-
-def main():
-    parser = argparse.ArgumentParser(description='SerialPlot test data generator')
-    parser.add_argument('port', help='Serial port or file (e.g. /dev/pts/3)')
-    parser.add_argument('--channels', type=int, default=2, help='Number of channels')
-    parser.add_argument('--samples', type=int, default=200, help='Samples per frame')
-    parser.add_argument('--wave', choices=['sine', 'saw', 'square'], default='sine')
-    parser.add_argument('--freq', type=float, default=0.5,
-                        help='Wave frequency (cycles per frame; 0.5 = half a sine wave, easy to observe)')
-    parser.add_argument('--amplitude', type=int, default=8000,
-                        help='Amplitude (i16 range, max 32767)')
-    parser.add_argument('--interval', type=float, default=0.05,
-                        help='Interval between frames (seconds)')
-    parser.add_argument('--frames', type=int, default=0,
-                        help='Number of frames (0=infinite)')
-    args = parser.parse_args()
-
-    count = 0
-    try:
-        with open(args.port, 'wb') as f:
-            print(f"Generating {args.channels}-channel {args.wave} wave → {args.port}")
-            print(f"  {args.samples} samples/frame, freq={args.freq} cycles/frame")
-            print(f"  amplitude={args.amplitude}, interval={args.interval}s")
-            print(f"  Protocol: sync=AA55, i16 LE, 1B size+checksum")
-            print()
-
-            while args.frames == 0 or count < args.frames:
-                count += 1
-                data = generate_wave(args.channels, args.samples, args.wave, args.freq, args.amplitude)
-                frame = make_frame(data)
-                f.write(frame)
-                f.flush()
-
-                vals = [data[ch][0] for ch in range(args.channels)]
-                vals_str = ", ".join(f"ch{ch}={v:+6d}" for ch, v in enumerate(vals))
-                print(f"  Frame #{count}: {vals_str} ... ({len(frame)} bytes)", end='\r')
-
-                time.sleep(args.interval)
-    except KeyboardInterrupt:
-        print(f"\nDone. {count} frames sent.")
-    except Exception as e:
-        print(f"Error: {e}", file=sys.stderr)
-        sys.exit(1)
-
-
-if __name__ == '__main__':
-    main()
diff --git a/tools/test_plot.py b/tools/test_plot.py
new file mode 100755
index 0000000..d33b58c
--- /dev/null
+++ b/tools/test_plot.py
@@ -0,0 +1,278 @@
+#!/usr/bin/env python3
+"""TCP server that sends plot waveform frames for the current xserial GUI."""
+
+import argparse
+import math
+import socket
+import struct
+import threading
+import time
+
+PLOT_ESCAPE = 0x1E
+PLOT_MARKER = ord("P")
+
+
+def build_frame(
+    sample_index: int,
+    channels: int,
+    plot_format: str,
+    samples_per_channel: int,
+    amplitude: float,
+    frequency_hz: float,
+    sample_rate_hz: float,
+) -> bytes:
+    values = []
+    if plot_format == "xy":
+        for offset in range(samples_per_channel):
+            t = (sample_index + offset) / sample_rate_hz
+            x = amplitude * math.cos(2 * math.pi * frequency_hz * t)
+            y = amplitude * math.sin(2 * math.pi * frequency_hz * t)
+            values.extend([x, y])
+        return struct.pack(f"<{len(values)}f", *values)
+
+    for offset in range(samples_per_channel):
+        t = (sample_index + offset) / sample_rate_hz
+        for ch in range(channels):
+            phase = 2 * math.pi * ch / max(channels, 1)
+            value = amplitude * math.sin(2 * math.pi * frequency_hz * t + phase)
+            values.append(value)
+    return struct.pack(f"<{len(values)}f", *values)
+
+
+def cobs_encode(payload: bytes) -> bytes:
+    if not payload:
+        return b"\x01"
+
+    out = bytearray([0])
+    code_index = 0
+    code = 1
+    for byte in payload:
+        if byte == 0:
+            out[code_index] = code
+            code_index = len(out)
+            out.append(0)
+            code = 1
+        else:
+            out.append(byte)
+            code += 1
+            if code == 0xFF:
+                out[code_index] = code
+                code_index = len(out)
+                out.append(0)
+                code = 1
+    out[code_index] = code
+    return bytes(out)
+
+
+def build_plot_packet(
+    payload: bytes,
+    channels: int,
+    samples_per_channel: int,
+    plot_format: str,
+) -> bytes:
+    format_id = {"interleaved": 0, "block": 1, "xy": 2}[plot_format]
+    header = bytearray()
+    header.extend(b"XP")
+    header.append(1)  # version
+    header.append(format_id)
+    header.append(8)  # f32
+    header.append(0)  # little-endian
+    header.append(channels)
+    header.extend(struct.pack("<H", samples_per_channel))
+    header.extend(struct.pack("<I", len(payload)))
+    header.extend(payload)
+    return bytes(header)
+
+
+def build_mixed_plot_frame(
+    payload: bytes,
+    channels: int,
+    samples_per_channel: int,
+    plot_format: str,
+) -> bytes:
+    packet = build_plot_packet(
+        payload=payload,
+        channels=channels,
+        samples_per_channel=samples_per_channel,
+        plot_format=plot_format,
+    )
+    return bytes([PLOT_ESCAPE, PLOT_MARKER]) + cobs_encode(packet) + b"\x00"
+
+def main():
+    p = argparse.ArgumentParser(description="xserial plot test server")
+    p.add_argument("--host", default="127.0.0.1")
+    p.add_argument("--port", type=int, default=8080)
+    p.add_argument("--channels", type=int, default=1)
+    p.add_argument(
+        "--format",
+        choices=("interleaved", "xy"),
+        default="interleaved",
+        help="plot format (default: interleaved)",
+    )
+    p.add_argument(
+        "--rate",
+        type=float,
+        default=1024,
+        help="samples/sec per channel (default: 1024)",
+    )
+    p.add_argument("--freq", type=float, default=1.0, help="sine Hz")
+    p.add_argument("--amp", type=float, default=100)
+    p.add_argument(
+        "--text-interval",
+        type=float,
+        default=1.0,
+        help="seconds between status text messages (default: 1.0)",
+    )
+    p.add_argument(
+        "--framelen",
+        type=int,
+        default=0,
+        help="fixed frame bytes (0=one sample per channel per frame)",
+    )
+    p.add_argument(
+        "--wire-format",
+        choices=("mixed", "raw"),
+        default="mixed",
+        help="mixed sends text+plot on one connection; raw sends plot only",
+    )
+    args = p.parse_args()
+
+    sample_size = 4  # f32
+
+    if args.channels <= 0:
+        raise SystemExit("--channels must be >= 1")
+    if args.format == "xy" and args.channels != 2:
+        raise SystemExit("--format xy requires --channels 2")
+    if args.rate <= 0:
+        raise SystemExit("--rate must be positive")
+    if args.text_interval <= 0:
+        raise SystemExit("--text-interval must be positive")
+    if args.framelen < 0:
+        raise SystemExit("--framelen must be >= 0")
+
+    bytes_per_sample_group = args.channels * sample_size
+    frame_bytes = args.framelen or bytes_per_sample_group
+    if frame_bytes % bytes_per_sample_group != 0:
+        raise SystemExit(
+            f"--framelen must be a multiple of {bytes_per_sample_group} bytes "
+            f"for {args.channels} channel f32 interleaved data"
+        )
+    samples_per_channel = frame_bytes // bytes_per_sample_group
+    frame_interval = samples_per_channel / args.rate
+    frame_rate = args.rate / samples_per_channel
+
+    def sample_values(sample_index: int) -> list[float]:
+        if args.format == "xy":
+            t = sample_index / args.rate
+            return [
+                args.amp * math.cos(2 * math.pi * args.freq * t),
+                args.amp * math.sin(2 * math.pi * args.freq * t),
+            ]
+
+        t = sample_index / args.rate
+        values = []
+        for ch in range(args.channels):
+            phase = 2 * math.pi * ch / max(args.channels, 1)
+            values.append(args.amp * math.sin(2 * math.pi * args.freq * t + phase))
+        return values
+
+    print(f"Listening {args.host}:{args.port} — Ctrl+C to stop")
+    print("GUI:")
+    print(f"  transport = TCP {args.host}:{args.port}")
+    if args.wire_format == "mixed":
+        print("  framer    = MixedTextPlot")
+        print("  decoder   = MixedTextPlot\n")
+    else:
+        print(f"  framer    = Fixed({frame_bytes})")
+        print(
+            f"  decoder   = Plot(f32, little-endian, {args.channels} channel, {args.format})\n"
+        )
+    print(f"sending {samples_per_channel} samples/frame at {args.rate:.1f} samples/sec")
+    print(f"effective frame rate: {frame_rate:.2f} fps\n")
+
+    stop_event = threading.Event()
+
+    def serve_stream() -> None:
+        srv = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        srv.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+        srv.bind((args.host, args.port))
+        srv.listen(1)
+        srv.settimeout(0.5)
+        try:
+            while not stop_event.is_set():
+                try:
+                    conn, addr = srv.accept()
+                except socket.timeout:
+                    continue
+                print(f"[conn +] {addr}")
+
+                started_at = time.perf_counter()
+                frame_count = 0
+                text_count = 0
+                sample_index = 0
+                next_text_at = started_at
+                try:
+                    while not stop_event.is_set():
+                        plot_payload = build_frame(
+                            sample_index=sample_index,
+                            channels=args.channels,
+                            plot_format=args.format,
+                            samples_per_channel=samples_per_channel,
+                            amplitude=args.amp,
+                            frequency_hz=args.freq,
+                            sample_rate_hz=args.rate,
+                        )
+                        if args.wire_format == "mixed":
+                            frame = build_mixed_plot_frame(
+                                payload=plot_payload,
+                                channels=args.channels,
+                                samples_per_channel=samples_per_channel,
+                                plot_format=args.format,
+                            )
+                        else:
+                            frame = plot_payload
+                        conn.sendall(frame)
+
+                        now = time.perf_counter()
+                        if args.wire_format == "mixed" and now >= next_text_at:
+                            values = sample_values(sample_index)
+                            joined = ", ".join(
+                                f"ch{index + 1}={value:8.3f}"
+                                for index, value in enumerate(values)
+                            )
+                            line = (
+                                f"t={now - started_at:7.3f}s "
+                                f"sample={sample_index:7d} {joined}\n"
+                            )
+                            conn.sendall(line.encode("utf-8"))
+                            text_count += 1
+                            next_text_at += args.text_interval
+
+                        sample_index += samples_per_channel
+                        frame_count += 1
+
+                        elapsed = time.perf_counter() - started_at
+                        wait = frame_count * frame_interval - elapsed
+                        if wait > 0:
+                            time.sleep(wait)
+                except (BrokenPipeError, ConnectionResetError):
+                    print(f"[conn -] {addr} ({frame_count} plot frames, {text_count} text lines)")
+                finally:
+                    conn.close()
+        finally:
+            srv.close()
+
+    stream_thread = threading.Thread(target=serve_stream, daemon=True)
+    stream_thread.start()
+
+    try:
+        while True:
+            time.sleep(0.5)
+    except KeyboardInterrupt:
+        print("\nstopped.")
+    finally:
+        stop_event.set()
+        stream_thread.join(timeout=1.0)
+
+if __name__ == "__main__":
+    main()