New hardware synth support added. Untested, so consider this experimental.

docs/user.md

@@ -100,6 +100,8 @@ driver=speechdDriver
 rate=0.5
 pitch=0.5
 volume=1.0
+hardware_device=auto
+hardware_baud_rate=9600
 
 [sound] 
 enabled=True
@@ -330,6 +332,19 @@ Fenrir automatically detects and provides audio feedback for progress indicators
 ### Speech Drivers
 - **speechdDriver** - Speech-dispatcher (recommended)
 - **genericDriver** - Command-line TTS (espeak, etc.)
+- **dectalkDriver** - Serial DECtalk-compatible hardware speech
+- **litetalkDriver** - Serial LiteTalk-compatible hardware speech
+- **doubletalkDriver** - Serial DoubleTalk LT-compatible hardware speech
+- **tripletalkDriver** - Serial TripleTalk-compatible hardware speech
+
+For hardware speech, set `speech#hardware_device` to `auto` or an explicit
+serial path. RPITalk gadget mode usually appears as `/dev/ttyACM0`; USB serial
+adapters usually appear as `/dev/ttyUSB0`; built-in serial ports may be
+`/dev/ttyS0`. The default baud rate is `9600`. `doubletalkDriver` targets
+DoubleTalk LT-style serial devices, not the internal DoubleTalk PC ISA card.
+USB TripleTalk devices work only if Linux exposes them as a serial tty such as
+`/dev/ttyACM0` or `/dev/ttyUSB0`; USB-only models with no tty device need a
+separate driver.
 
 ### Sound Drivers  
 - **genericDriver** - Sox-based (default)