There is also a serial port labeled SCTX and SCRX, both of these lines appear to be transmit only from the top CPU board down to the bottom transceiver board. As the radio is tuned from one frequency to another the SCRX line has a lot of activity, when the transmitter is keyed up the SCTX line has activity. Here is a sample of what is seen on the SCRX line.
{| class="wikitable mw-collapsible mw-collapsed"
|+
!SCRX
|-