Improvements to Dectalk driver.

src/fenrirscreenreader/fenrirVersion.py

@@ -4,5 +4,5 @@
 # Fenrir TTY screen reader
 # By Chrys, Storm Dragon, and contributors.
 
-version = "2026.07.25"
+version = "2026.07.26"
 code_name = "testing"

src/fenrirscreenreader/speechDriver/dectalkDriver.py

@@ -10,16 +10,17 @@ from fenrirscreenreader.speechDriver.hardwareSerialDriver import (
 
 
 class driver(hardware_serial_driver):
-    cancel_command = b"\x18"
+    cancel_command = b"\x03"
+    use_xon_xoff = True
 
     def _speak_bytes(self, text):
-        return self._clean_text(text).encode("ascii", errors="replace") + b"\x01"
+        return self._clean_text(text).encode("ascii", errors="replace") + b"\x0b"
 
     def _rate_command(self, rate):
         return self._setting_command("ra", self._scale(rate, 75, 650))
 
     def _pitch_command(self, pitch):
-        return self._setting_command("dv ap", self._scale(pitch, 50, 180))
+        return self._setting_command("dv ap", self._scale(pitch, 50, 350))
 
     def _volume_command(self, volume):
         return self._setting_command("vo", self._scale(volume, 0, 100))

src/fenrirscreenreader/speechDriver/hardwareSerialDriver.py

@@ -27,6 +27,7 @@ class SpeakQueue(Queue):
 class hardware_serial_driver(speech_driver):
     cancel_command = b""
     default_baud_rate = 9600
+    use_xon_xoff = False
 
     def __init__(self):
         speech_driver.__init__(self)
@@ -176,6 +177,10 @@ class hardware_serial_driver(speech_driver):
             attrs[5] = baud_rate
             attrs[6][termios.VMIN] = 0
             attrs[6][termios.VTIME] = 0
+            if self.use_xon_xoff:
+                attrs[0] |= termios.IXON
+                attrs[0] &= ~(termios.IXOFF | termios.IXANY)
+            else:
                 attrs[0] &= ~(termios.IXON | termios.IXOFF | termios.IXANY)
             termios.tcsetattr(port, termios.TCSANOW, attrs)
             return port

tests/unit/test_hardware_speech_drivers.py

@@ -1,5 +1,6 @@
 import os
 import select
+import termios
 import time
 from unittest.mock import ANY
 from unittest.mock import Mock
@@ -64,7 +65,7 @@ def test_dectalk_driver_speaks_printable_text(serial_pair):
     speech_driver, master_fd = initialized_driver(dectalkDriver, serial_pair)
     try:
         speech_driver.speak("Hello\nworld ☃")
-        assert read_available(master_fd, 13) == b"Hello world  \x01"
+        assert read_available(master_fd, 13) == b"Hello world  \x0b"
     finally:
         speech_driver.shutdown()
 
@@ -73,12 +74,22 @@ def test_dectalk_driver_writes_settings_and_cancel(serial_pair):
     speech_driver, master_fd = initialized_driver(dectalkDriver, serial_pair)
     try:
         speech_driver.set_rate(1.0)
-        speech_driver.set_pitch(0.0)
+        speech_driver.set_pitch(1.0)
         speech_driver.set_volume(0.5)
         speech_driver.cancel()
-        assert read_available(master_fd, 33) == (
-            b"[:ra 650][:dv ap 50][:vo 50]\x18"
-        )
+        expected = b"[:ra 650][:dv ap 350][:vo 50]\x03"
+        assert read_available(master_fd, len(expected)) == expected
+    finally:
+        speech_driver.shutdown()
+
+
+def test_dectalk_driver_enables_xon_xoff_flow_control(serial_pair):
+    speech_driver, _ = initialized_driver(dectalkDriver, serial_pair)
+    try:
+        input_flags = termios.tcgetattr(speech_driver.serial_port)[0]
+        assert input_flags & termios.IXON
+        assert not input_flags & termios.IXOFF
+        assert not input_flags & termios.IXANY
     finally:
         speech_driver.shutdown()