A novel high-speed interface circuit saving wiring equipment

A high-speed integrated interface circuit is described, which is capable of transmitting and receiving full duplex digital signals on a twisted pair line. Thus two independent messages may be transmitted on one line at the same time. A push-pull transmitter and a differential amplifier as receiver provide a common-mode rejection of more than 1 V in either the positive or negative direction. Output signals and input threshold are compatible with ECL F100K. Compared to conventional interface transceivers this approach has the following advantages: (1) the needed number of lines and connectors is halved; (2) only one type of circuit is necessary, because both transmitter and receiver are housed in one package; (3) the reduced number of line pins leaves space for more transceiver circuits in one package.