RimuCAT Guide

RimuCAT bridges the FlexRadio network protocol to a standard CAT interface, letting logging programs, digital-mode software, and automation tools control your radio from Linux.

Connecting RimuCAT CAT Port

RimuCAT · TCP · Virtual Serial Port · FlexRadio 6000 · 8000 · Aurora

RimuCAT interface with an active CAT connection

What RimuCAT Does

RimuCAT is the CAT control component of the RimuSDR suite. It translates the FlexRadio network protocol into a standard CAT interface that external software can connect to over TCP or through a virtual serial port.

TCP Connections

The recommended connection method for modern software such as WSJT-X and N1MM+.

Create a TCP listener on any port you choose
Configure external software as FlexRadio 6xxx rig type
Point it to localhost and the port you selected
Multiple TCP connections supported simultaneously

Virtual Serial Ports

For software that only supports serial port CAT, such as Fldigi and older logging programs.

Creates a virtual port that appears under /dev/
Behaves like a real serial device
Works with any software that supports serial CAT control
Multiple virtual ports can be created simultaneously

What CAT Provides

Full bidirectional control of frequency, mode, and transmit state.

Read and set VFO frequency
Read and set operating mode
PTT keying for transmit control
Radio state updates pushed to connected software
FlexRadio 6xxx command set for TCP connections

Connecting RimuCAT to Your Radio

RimuCAT must be connected to the same FlexRadio station as RimuSDR before any CAT connections will work. Follow these steps to get RimuCAT running.

Start RimuSDR first

RimuSDR must be connected to the radio before RimuCAT is started. RimuCAT relies on the same station connection that RimuSDR establishes.

Open RimuCAT

Launch RimuCAT from your applications menu or from the RimuSDR interface. RimuCAT will appear in its own window alongside RimuSDR.

Connect to the station

In RimuCAT, select the same station that RimuSDR is connected to and click Connect. RimuCAT will show a connected status once it has established its own link to the radio.

Idle until a connection is created

After connecting RimuCAT to the station, it will sit idle until you create at least one TCP or virtual serial port CAT connection. This is expected behavior — RimuCAT does not expose any CAT endpoint until you configure one.

RimuCAT interface showing connection status and CAT connection list — RimuCAT after connecting to a station and creating a TCP CAT connection. The connection list shows the type, port, and status of each configured endpoint.

CAT Port

The CAT port provides bidirectional radio control — frequency, mode, and PTT — to external software. Multiple simultaneous CAT connections are supported; use a different port number for each application and they can all control the radio at the same time.

1 Give the port a name (e.g. WSJT-X)

2 Select Protocol CAT

3 Select the Port Type of TCP

4 Enter an unused port above 1024

5 Select the Slice to associate with the port

6 Click Save to create the port

1 Give the port a name (e.g. Fldigi)

2 Select Protocol CAT

3 Select the Port Type of Virtual Serial

4 Select the Slice to associate with the port

5 Click Save to create the port

6 Note the device path shown in RimuCAT (e.g. /tmp/ttyCAT0) and enter it in your application

The virtual port exists only while RimuCAT is running and connected. If RimuCAT is closed or disconnected, the port disappears and applications holding it open will need to reconnect.

RimuCAT virtual serial port configuration

1 Give the port a name (e.g. Logger)

2 Select Protocol CAT

3 Select the Port Type of Hardware Serial

4 Choose the physical port device from the list (e.g. /dev/ttyUSB0)

5 Set the baud rate to match your connected hardware or software

6 Select the Slice to associate with the port

7 Click Save to create the port

On Linux, access to serial port devices requires membership in the dialout group. If the port does not appear or RimuCAT cannot open it, add your user account to the group with sudo usermod -aG dialout $USER and then log out and back in for the change to take effect.

RimuCAT hardware serial port configuration

PTT Port

The PTT port provides a dedicated transmit keying interface separate from CAT control. Use a PTT port when your application needs to key the radio for transmit independently of CAT commands.

1 Give the port a name (e.g. PTT-VSP)

2 Select Protocol PTT

3 Select the Port Type of Virtual Serial

4 Select RTS or DTR to match what your application uses for PTT keying

5 Select the Slice to associate with the port

6 Click Save to create the port

7 Note the device path shown in RimuCAT and enter it in your application's PTT port setting

RimuCAT virtual serial PTT port configuration

1 Give the port a name (e.g. PTT-Serial)

2 Select Protocol PTT

3 Select the Port Type of Hardware Serial

4 Choose the physical port device from the list (e.g. /dev/ttyUSB0)

5 Select RTS or DTR to match what your hardware uses for PTT keying

6 Select the Slice to associate with the port

7 Click Save to create the port

On Linux, access to serial port devices requires membership in the dialout group. If RimuCAT cannot open the port, add your user account to the group with sudo usermod -aG dialout $USER and then log out and back in for the change to take effect.

RimuCAT hardware serial PTT port configuration

Related Guides

Step-by-step integration guides for connecting digital-mode and logging applications to RimuSDR.

RimuSDR User Guide

Full coverage of the RimuSDR suite including radio connection, panadapter controls, DAX audio configuration, CAT setup, and the CWX keyer.

WSJT-X Setup Guide

Configure WSJT-X for FT8, FT4, and related weak-signal digital modes using RimuDAX for audio and RimuCAT TCP for CAT control.

Fldigi Setup Guide

Configure Fldigi for HF digital modes using RimuDAX audio and a RimuCAT virtual serial port for CAT control.

Installation Guide

Download and install RimuSDR, RimuDAX, and RimuCAT on Debian, Ubuntu, Raspberry Pi, or via AppImage, and activate your license.