Telephonic communications – Supervisory or control line signaling – Using line or loop condition detection
Patent
1994-08-04
1996-06-11
Hofsass, Jeffery
Telephonic communications
Supervisory or control line signaling
Using line or loop condition detection
379 67, 379100, 379 88, H04M 322
Patent
active
055264204
ABSTRACT:
There is disclosed a control circuit for switching between a facsimile unit and an automatic answering telephone unit. A current detecting circuit with satisfactory linearity between the mutually insulated input and output sides is used for detecting a DC current on a communication line, indicating a communication state of the telephone unit and also for detecting an AC signal, representing a speech communication signal and used for recording an incoming message in the automatic answering telephone unit. This structure allows to insulate the recording circuit and the facsimile circuit from the communication line without a transformer, thereby reducing cost and dimension of the apparatus.
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Nishii Teruyuki
Terajima Hisao
Toda Kozo
Watanabe Tsunehiro
Canon Kabushiki Kaisha
Hofsass Jeffery
Saint-Surin Jacques M.
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