Interface Circuit For Transmitting And Receiving Digital Signals Between Devices

Abstract

A video signal and an audio signal are TMDS transmitted from a source device to a sink device. Through a reserved line and a HPD line provided separately from a TMDS transmission line, an Ethernet™ signal is bidirectionally transmitted, and also, a SPDIF signal is transmitted from the sink device to the source device. The Ethernet™ signal bidirectionally transmitted between Ethernet™ transmitter/receiver circuits is differentially transmitted by an amplifier and is received by the amplifier. The SPDIF signal from a SPDIF transmitter circuit is common-mode transmitted from an adder and is received by the adder to be supplied to the SPDIF receiver circuit.

1 . An interface circuit comprising:
 a first transmitting section for transmitting a first signal as a differential signal to an external device through a transmission line; and   a second transmitting section for transmitting a second signal, being multiplexed to the transmission line, as a common-mode signal to the external device.