Multiplexing Techniques for signal transmission have been used for many years in the communication industry. Their use in the aviation industry, is best typified by the MIL-STD-1553 type systems used in military aircraft and the ARINC 429 type systems now being applied to some large transports. In the General Aviation area, however, the use of multiplexing has been restricted to intercommunication within a system. An example is the link between a panel mounted radio control head and a remote radio receiver/transmitter where the requested frequency is often transmitted by a serial digital link. This paper's emphasis is on the expansion of multiplexing usage to intersystem transmission of data in a General Aviation Aircraft.