Enable CAT TCP so N1MM, Log4OM, WSJT-X can control the radio

The CAT Control applet runs up to four rigctld-compatible TCP servers, one per slice channel (A–D), so external logging and contest software can control the radio over a network socket. Use this page to start those servers and point your logging software at the correct port.

Before you start

• AetherSDR must be connected to the radio. The CAT applet requires an active radio connection.
• Decide which base port to use. The default is 4532. Channels A, B, C, and D bind to base, base+1, base+2, and base+3 respectively.
• Make sure no other application (including a standalone rigctld instance) is already listening on those ports.

Steps

1. Click the CAT tray button on the right sidebar to open the CAT Control applet. The applet is hidden by default.
2. Check the value in the Base field. The default is 4532. Change it if needed (valid range: 1024–65535). Press Enter or click away to confirm; out-of-range values snap back to 4532.
3. Click Enable TCP. The button highlights green when active.
4. Verify the channel rows. Each row labelled A, B, C, or D should update from (stopped) to :<port> (0 clients) once the servers are listening.
5. In your logging or contest software (N1MM, Log4OM, WSJT-X, or similar), configure the CAT connection as rigctld (net) and enter localhost (or the AetherSDR machine's IP address) and the port for the channel you want to control — for example, 4532 for channel A or 4533 for channel B.
6. When the external software connects, the channel row updates to :<port> (1 client).

What each control does

Control	Default	Valid range	Persisted key	Behavior
Enable TCP	Off	On / Off	—	Starts or stops all four rigctld TCP servers. Also writes the current base port to CatTcpPort.
Base	4532	1024–65535	CatTcpPort	Sets the base TCP port. Channel A uses this port; B, C, and D use base+1, base+2, base+3. If servers are already running, they restart on the new ports immediately.
Enable TTY	Off	On / Off	—	Starts or stops PTY symlinks (/tmp/AetherSDR-CAT-A through D) for serial-style access. Not needed for TCP-based software.
Channel rows (A–D)	(stopped)	—	—	Shows each channel's TCP status and connected client count. Badge colour matches the slice colour.

Tips

• If you only use one logging program at a time, channel A on port 4532 is sufficient. Channels B–D exist for running multiple programs simultaneously against different slices.
• To have the TCP servers start automatically every time AetherSDR launches, use Settings > Autostart rigctld with AetherSDR.
• Changing the Base value while Enable TCP is active restarts all running servers on the new ports immediately. Update your logging software's port setting to match before reconnecting.

Troubleshooting

• Channel row stays (stopped) after clicking Enable TCP — Another process is likely already listening on that port. Choose a different base port, or stop the conflicting application.
• Logging software shows "connection refused" — Confirm Enable TCP is on (button is green) and that you are using the correct port number for the channel. If AetherSDR is on a remote machine, use that machine's IP address rather than localhost.
• Client count does not increment — The software connected but immediately disconnected. Check that your logging software is set to rigctld (network) mode, not a direct serial or Hamlib mode that expects a different protocol.

Related

• CAT Control overview
• Change the base TCP port
• Autostart CAT servers with AetherSDR
• Enable CAT PTY so Linux/macOS apps can open a serial-style CAT port
• Setting up digital modes (FT8, WSJT-X, fldigi)