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Connect to UART serial ports on Lagerboxes for serial communication with devices.
Syntax
lager uart [NETNAME] [OPTIONS]
Arguments
| Argument | Description |
|---|
NETNAME | UART net name (optional if default is set) |
Options
| Option | Description |
|---|
--box BOX | Lagerbox name or IP address |
--baudrate RATE | Baudrate (e.g., 9600, 115200) |
--bytesize SIZE | Data bits (5, 6, 7, 8) |
--parity MODE | Parity: none, even, odd, mark, space |
--stopbits BITS | Stop bits (1, 1.5, 2) |
--xonxoff / --no-xonxoff | Software flow control |
--rtscts / --no-rtscts | Hardware flow control (RTS/CTS) |
--dsrdtr / --no-dsrdtr | Hardware flow control (DSR/DTR) |
-i / --interactive | Enable input mode for typing |
--opost / --no-opost | Convert \n to \r\n on output |
--line-ending MODE | Line ending: lf, crlf, cr (default: lf) |
Usage
Read-Only Mode (Default)
# Monitor serial output
lager uart SERIAL1 --box my-lager-box
# With specific baudrate
lager uart SERIAL1 --baudrate 115200
Interactive Mode
# Type commands and see responses
lager uart SERIAL1 --interactive
# With specific settings
lager uart SERIAL1 -i --baudrate 9600 --parity none
Get Serial Port Info
# Show device path for a UART net
lager uart SERIAL1 serial-port
Serial Configuration
Baudrate
Common baudrates:
- 9600 (default for many devices)
- 19200
- 38400
- 57600
- 115200 (common for embedded development)
- 230400
- 460800
- 921600
| Setting | Options | Default |
|---|
| Bytesize | 5, 6, 7, 8 | 8 |
| Parity | none, even, odd, mark, space | none |
| Stopbits | 1, 1.5, 2 | 1 |
Flow Control
| Type | Options | Description |
|---|
| Software | --xonxoff | XON/XOFF characters |
| Hardware | --rtscts | RTS/CTS pins |
| Hardware | --dsrdtr | DSR/DTR pins |
Line Endings
| Mode | Sequence | Use Case |
|---|
lf | \n | Unix/Linux |
crlf | \r\n | Windows |
cr | \r | Legacy systems |
--opost to automatically convert line endings on output.
Supported USB Serial Adapters
The following USB-to-serial adapters are automatically detected and supported:
| Adapter | VID:PID | Description |
|---|
| Prolific USB-Serial | 067b:23a3 | Common USB-Serial adapter |
| Silicon Labs CP210x | 10c4:ea60 | Popular embedded dev boards |
| FTDI FT232R | 0403:6001 | Single-channel USB-Serial |
| FTDI FT4232H | 0403:6011 | Quad-channel USB-Serial |
| ESP32 USB JTAG/Serial | 303a:1001 | Built-in ESP32-S3/C3 USB |
lager instruments and can be configured as UART nets.
Device Path Support
UART nets can reference devices two ways:
USB Serial Number (preferred):
Net configured with USB serial number
Automatically resolves to correct /dev/ttyUSBx
# When adapter has no serial number
lager uart /dev/ttyUSB0 --baudrate 115200
Examples
# Basic serial monitor
lager uart DEBUG_UART --box lab-gw
# Interactive shell with common embedded settings
lager uart CONSOLE -i --baudrate 115200
# Legacy device with specific format
lager uart LEGACY --baudrate 9600 --bytesize 7 --parity even --stopbits 2
# With software flow control
lager uart MODEM --xonxoff
# Windows-style line endings
lager uart TERMINAL --line-ending crlf --opost
WebSocket Connection
The UART command uses WebSocket for communication:
- Provides real-time bidirectional data
- Supports both read-only and interactive modes
- Automatically reconnects on connection loss
Troubleshooting
Device Not Found
# List available instruments to find UART devices
lager instruments --box my-lager-box
# Check if USB serial adapter is connected
ssh lagerdata@my-lager-box 'ls -la /dev/ttyUSB*'
Permission Denied
# Ensure udev rules are installed
lager update --box my-lager-box --yes
No Output
- Check baudrate matches device
- Verify TX/RX connections
- Try interactive mode to test input
- Check flow control settings
Notes
- Interactive mode requires a TTY terminal
- USB serial numbers are truncated for display
- Default net can be set with
lager defaults add --uart-net
- Connection retry logic handles temporary disconnections
See Also
