Autostart CAT servers with AetherSDR¶

Configure AetherSDR to start the rigctld TCP servers and/or PTY virtual serial ports automatically each time the application launches, so external logging and contest software is ready without manual intervention.

Before you start¶

AetherSDR must be connected to a FLEX-8600 radio before the CAT servers can operate. The autostart setting is saved regardless, but servers only become active once a radio connection is established.
Decide whether you need TCP, PTY (Linux/macOS only), or both. TCP works on all platforms; PTY is for applications that expect a serial device path.
PTY symlink paths are located in per-user runtime directories for security:
Linux: $XDG_RUNTIME_DIR/aethersdr/cat-A through cat-D
macOS: ~/Library/Caches/AetherSDR/cat-A through cat-D

Steps¶

Enable autostart for TCP servers¶

Open Settings > Autostart rigctld with AetherSDR.
Click the item to place a checkmark next to it.

AetherSDR will now start all four rigctld TCP servers automatically on the next launch. The base port persisted in CatTcpPort (default 4532) is used; channels bind to port, port+1, port+2, and port+3.

Enable autostart for PTY virtual serial ports¶

Open Settings > Autostart CAT with AetherSDR.
Click the item to place a checkmark next to it.

AetherSDR will now create the PTY symlinks under the per-user runtime paths automatically on the next launch: - Linux: $XDG_RUNTIME_DIR/aethersdr/cat-A through cat-D - macOS: ~/Library/Caches/AetherSDR/cat-A through cat-D

Verify the current session without restarting¶

If you want the servers running immediately in the current session as well:

Click the CAT tray button on the right sidebar to open the CAT Control applet.
Click the master Enable button (labeled Disabled by default) to start all CAT servers now. The button text changes to Enabled and the per-channel rows become editable.
In each channel row you wish to use, click the checkbox next to the channel badge to enable that channel's TCP server and/or PTY symlink.

The channel rows (A, B, C, D) will update from (stopped) to :<port> (0 clients) as each server comes up. Each channel row also displays the current PTY path.

Per-channel enable checkboxes¶

In v26.7.4, each channel row (A, B, C, D) gained an individual enable checkbox. These checkboxes have a high-contrast style that uses a filled accent colour when checked, making the on/off state readable at a glance against the dark applet background.

When the master Enable button is turned off, all per-channel checkboxes are disabled and the servers stop.
When the master Enable button is turned on, you can independently enable or disable each channel by clicking its checkbox.
Each checkbox controls both the TCP server and PTY symlink for that channel simultaneously.

CAT Control applet overview¶

The CAT Control applet runs up to four rigctld-compatible TCP servers (and PTY symlinks on Linux/macOS) so external logging and contest software can control one slice per channel. Slices A–H each expose a TTY (per-user runtime path) and a TCP port (4532–4539).

What each control does¶

Control	Kind	Default	Setting Key	Notes
`Enable` master button	Toggle button	`Disabled`	`CatEnabled`	Starts/stops all CAT servers. Button text changes to `Enabled` when active.
Per-channel checkboxes	Checkbox	Unchecked	None	High-contrast style; visible only when master `Enable` is on.
`Base`	Text field	`4532`	`CatTcpPort`	Base TCP port; channels bind to port, port+1, port+2, port+3. Out-of-range values snap back to 4532.
A/B/C/D channel rows	Indicator	`(stopped)`	None	Each row shows channel badge, TCP status, PTY path.

Per-channel TCP status indicator¶

State	Meaning
`(stopped)`	Server not running
`:<port> (1 client)`	Server active with 1 connected client
`:<port> (N clients)`	Server active with N connected clients

Per-channel PTY path indicator¶

State	Meaning
`stopped`	No PTY active
`<path>`	Symlink path when PTY is running (e.g., `/run/user/1000/aethersdr/cat-A` on Linux or `~/Library/Caches/AetherSDR/cat-A` on macOS)

VFO selection persistence¶

The VFO combos in each channel row are bounded by the radio's slice-receiver count. If you reconnect to a smaller radio, a previously-chosen slice that no longer exists is preserved in settings and reappears when the slices return. Only a genuine, representable selection (including a deliberate —) is persisted.

Tips¶

The master Enable button in the applet is linked to the Autostart rigctld with AetherSDR and Autostart CAT with AetherSDR settings. Toggling the button updates both autostart preferences at the same time, so you can use the applet button instead of the Settings menu if you prefer.
If you change the Base port after enabling CAT servers, the new port is saved to CatTcpPort and the running servers restart on the new base immediately. The saved value is used on the next autostart as well.
In v26.5.3, AetherSDR includes a native Hamlib NET rigctl implementation, replacing the need for a standalone rigctld bridge. Slices A–H each expose a TTY (per-user runtime path) and a TCP port (4532–4539).
PTY symlink creation uses atomic replacement (symlink + rename) to prevent TOCTOU race conditions (GHSA-qxhr-cwrc-pvrm).

Troubleshooting¶

Servers do not start after launch even though autostart is enabled — The radio must be connected before the servers become active. Confirm the connection state in the title bar and retry once connected.
Per-channel checkboxes are greyed out — Click the master Enable button first to enable CAT servers before configuring individual channels.
PTY symlinks do not appear — The PTY feature is only functional on Linux and macOS. On Windows, PTY has no effect. On Linux, verify that $XDG_RUNTIME_DIR is set (typically /run/user/<uid>).
Port already in use — If another application occupies a port in the Base–Base+3 range, the corresponding server will fail silently. Change the Base value in the CAT Control applet to an unused port range and re-enable.
Channel badge colours appear incorrect — Slice colours are managed dynamically. If badges show unexpected colours, disconnect and reconnect to the radio so that slice colour assignments are refreshed.