Interface unit for peripheral units used with telephone

摘要

The interface (10) is a compact unit with buffer amplifiers, switches and connectors. It also incorporates a volume control (32). The primary connection (12) is to a fixed (14) or cordless (16) telephone instrument. The system can be powered by an external power supply unit (36). A connection (38) is available for a "waiting" music generator (40). Another connection (28) is provided for a recording system, such as an answerphone (30). An audio signal connector (18) can be used to connect a headset (20), a handset (22), a loudspeaker (24) or cassette recorder (26). A built-in transmitter circuit (44a) is used to send signals to a cordless speaker (42). A receiver can receive the signals from a cordless microphone (24).