OTRSP port¶
The OTRSP port implements the Open Two Radio Switching Protocol for SO2R contest operation. It switches receive audio and the transmit slice between two slices on the one radio, so a logger treats your FlexRadio as two stations.
An OTRSP port binds two slices rather than one.
Create both slices first
The two slices must exist on the radio before the port can switch between them. Create them in RimuSDR first.
Virtual serial¶
- Give the port a name, for example
OTRSP. - Set Protocol to OTRSP.
- Set Port Type to Virtual Serial.
- Select the Radio 1 Slice and the Radio 2 Slice.
- Click Save.
- Note the device path shown in RimuCAT, for example
/tmp/ttyOTRSP0, and enter it as the SO2R device in your logger.
TCP¶
- Give the port a name, for example
OTRSP. - Set Protocol to OTRSP.
- Set Port Type to TCP.
- Leave the port at
60001, the OTRSP default, unless it is in use. - Select the Radio 1 Slice and the Radio 2 Slice.
- Click Save.
How the commands map¶
RX commands set which slice you hear, and where it sits in the stereo image.
TX commands set which slice transmits.
The port mirrors the resulting audio state to the transmit monitor and the CW sidetone.

