apparatus , and an accompanying method , for transmitting a frame synchronization signal and a data signal simultaneously through a serial transmission medium . specifically within a data transmitter , a frame synchronization signal , a clock signal and a data signal , are encoded to form a single bi - phase mark signal having the frame synchronization signal incorporated into the bi - phase mark signal as a phase - shift . the bi - phase mark signal is then transmitted through a suitable serial transmission medium . a receiver , connected to the transmission medium , receives and amplifies an incoming bi - phase mark signal appearing on the medium , and , in turn , synthesizes the clock , frame synchronization , and data signals from this bi - phase mark signal .