Abstract: An interface device serving as a bridge between a telephone-based bus with a plurality of TDM channels and a high speed data network to permit mixed data, voice, and video signals to be exchanged between the telephone bus and the data network, comprises a serial port for connection to the telephone bus; a parallel port for connection to the high speed data network; a bidirectional serial-to-parallel/parallel-to-serial converter connected to the serial port; and a rate converter circuit between the bidirectional converter and said parallel port, the rate converter circuit including a time-slot interchange device to permit rate adaptation with constant throughput delay and switching between the TDM channels.