FERNSPRECHTEILNEHMERSTATION

摘要

A telephone subscriber station has a base set and a cordless hand set. The transmission between the base and hand set occurs by way of infrared transmitters and infrared receivers. Pulse phase modulation who is particularly suited for the speech transmission. Various functions are remotely controlled from the cordless hand set by the transmission of special characters. The special characters are transmitted as pulse sequences having differing frequencies. Thereby, a specific frequency is assigned to each special character. A call device comprises keys and a controllable pulse generator. A frequency recognition circuit is provided in the receiver at the base set and assigns the received pulse sequences to the special characters and has corresponding control functions. A monitoring circuit monitors the synchronization between the hand set and the base set and disconnects the telephone connection given a transmission which is disrupted over a longer interval.