The MARM-2000 airborne multiplexer unit is used to transmit multiple asynchronous PCM and video channels as a single high speed PCM channel. The RMOR-2000 receives the real time transmitted PCM channel and reproduces the multiple asynchronous PCM and video channels. The real time PCM output of the MARM-2000 unit can be up to 20 Mbps encoded in NRZ-L or RNRZ-L.