CAT Control overview¶
CAT Control lets external logging and contest software command the FLEX-8600 through rigctld-compatible interfaces. AetherSDR runs up to four independent servers — one per slice (A, B, C, D) — over TCP, virtual serial ports (PTY), or both simultaneously.
In v26.5.3, the PTY symlink location was moved from /tmp to per-user runtime directories to fix a cross-user symlink vulnerability (GHSA-qxhr-cwrc-pvrm). Atomic symlink replacement via symlink(.tmp) + rename(.tmp, final) closes the TOCTOU window.
Before you start¶
- A FLEX-8600 must be connected. The CAT Control applet requires an active radio connection.
- The CAT applet is hidden by default. Click the CAT tray button on the right sidebar to show it.
How it works¶
Each of the four channels (A, B, C, D) maps to one radio slice. When TCP is enabled, each channel listens on its own port starting at the base port: channel A on Base, B on Base+1, C on Base+2, D on Base+3. When TTY is enabled on Linux or macOS, each channel creates a PTY symlink that logging software can open as a serial device.
External programs connect to whichever channel controls the slice they want to operate. Multiple clients can connect to the same channel simultaneously; the per-channel status row shows the current client count.
AetherSDR can start the TCP servers and PTY links automatically at launch via Settings > Autostart rigctld with AetherSDR and Settings > Autostart CAT with AetherSDR.
What each control does¶
| Control | Kind | Default | Valid range | Persisted key | Behavior |
|---|---|---|---|---|---|
| Enable TCP | Toggle button | Off | — | — | Starts or stops all four rigctld TCP servers on ports Base through Base+3. Also writes the current base port to CatTcpPort. |
| Enable TTY | Toggle button | Off | — | — | Starts or stops all four PTY symlinks under $XDG_RUNTIME_DIR/aethersdr/cat-A through cat-D (Linux) or ~/Library/Caches/AetherSDR/cat-A through cat-D (macOS). Available on Linux and macOS only. |
| Base | Text field | 4532 | 1024–65535 | CatTcpPort |
Sets the base TCP port. Values outside the valid range snap back to 4532. If TCP servers are running when you change this value, they restart on the new ports immediately. |
| A / B / C / D channel rows | Indicator | (stopped) | — | — | Each row shows a colour-coded slice badge, the TCP status (for example :4532 (1 client) or (stopped)), and the PTY symlink path for that channel. |
Per-channel indicators¶
| Indicator | States | Meaning |
|---|---|---|
| Per-channel TCP status | (stopped), :<port> (1 client), :<port> (N clients) |
Server state and connected client count per channel. |
| Per-channel PTY path | stopped, running PTY path |
Symlink path logging software can open as a serial device. Located under $XDG_RUNTIME_DIR/aethersdr/cat-A (Linux) or ~/Library/Caches/AetherSDR/cat-A (macOS). |
Tips¶
- If a port is already in use by another application, the server for that channel will fail to start. Change
Baseto a free port range and click Enable TCP again. - The PTY symlink paths are computed from per-user runtime directories. On Linux, paths are under
$XDG_RUNTIME_DIR/aethersdr/cat-Athroughcat-D. On macOS, paths are under~/Library/Caches/AetherSDR/cat-Athroughcat-D. The exact path appears in the channel row when the PTY is running. - You can run TCP and TTY at the same time on the same channel.