CXTRM Command - Serial Port Speed
Configures the speed (baudrate) of the serial/terminal port.
What is it used for?
| Use case | Description |
|---|---|
| 🔌 Compatibility | Adjust speed for external devices |
| ⚡ High speed | Transfer data quickly |
| 📡 Distance | Reduce speed for long cables |
| 🔧 Diagnostics | Communication with configuration tools |
Commands
Configure
SCXTRpaa..aaQuery
QCXTRpResponse
RCXTRpaa..aaParameters
| Parameter | Description | Values |
|---|---|---|
| p | Port number | 0 or M = Main, 1 = Port 1, 2 = Port 2 |
| aa..aa | Speed (baudrate) | 4800, 9600, 19200, 38400, 57600, 115200, 230400, 460800, 921600 |
Examples
Main port to 9600 baud (standard)
>SCXTR09600<
>SCXTRM9600< # Equivalent using alias MMain port to 115200 baud (high speed)
>SCXTR0115200<Useful for rapid data transmission.
Main port to 38400 baud (since v1.09.28)
>SCXTR038400<
>RCXTR038400< # the response already comes out at 38400For external devices that talk at 38400 (over RS232, for example).
Port 1 to 19200 baud
>SCXTR119200<Port 2 to 4800 baud
>SCXTR24800<Supported Speeds
| Baudrate | Typical application |
|---|---|
| 4800 | Legacy devices |
| 9600 | Standard - Most applications |
| 19200 | Moderate data transfer |
| 38400 | External devices over RS232 · since v1.09.28 |
| 57600 | External devices over RS232 · since v1.09.28 |
| 115200 | High speed for rapid downloads |
| 230400 | Datalog download |
| 460800 | Datalog download |
| 921600 | Maximum supported speed |
2400 baud is not supported: the serial driver does not accept it and the device answers CMDERR.
The lowest available speed is 4800.
Notes
Important: Both ends (device and terminal) must be configured with the same speed. Incorrect configuration generates illegible characters.
The change is immediate, and the response already comes out at the new speed. If you send SCXTR0 from a terminal at 115200, the RCXTR confirming the change arrives at the new speed and you won’t see it: reconnect the terminal at that speed. The speed is saved and kept across reboots.
38400 and 57600 since firmware v1.09.28. On an earlier version the device answers CMDERR and the speed does not change. Applies to Spider and Smart: on Zero the console is native USB and the speed has no effect.
- Speed change requires restarting serial connection
- Incorrect speed = impossible communication
Compatibility
See Also
- CXTY Command - Serial capture configuration
- Serial Port - Connection guide