Intercommunication system

Details Intercommunication system Intercommunication system

1994-11-15

1996-04-09

Chin, Stephen

Telephonic communications

Private or single line system

Doorbell system

381173, 381194, 379170, H04M 160, H04M 900, H04R 2500

Patent

active

055068960

ABSTRACT:
An intercommunication system for transmitting signals through a door, and having piezo transducer devices mountable on each side of the door, a matrix of analog switches connecting the piezo transducer devices to the input and output of a bridge amplifier, and a TALK switching device which controls which piezo transducer device is connected to the bridge amplifier through the analog switches as a speaker or as a microphone.

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