Howler tone sending-out system in time-division electronic exchanges
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United States of America Patent
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-
Feb 26, 1985
Grant Date -
N/A
app pub date -
Jan 27, 1982
filing date -
Feb 12, 1981
priority date (Note) -
Expired
status (Latency Note)
Importance
Abstract
A subscriber circuit in a time-division telephone switching system having a supervisory circuit connected to a subscriber telephone set for supervision of incoming calls, call-answering, line-busy and on-hook supervision on the telephone set. A common control circuit receives signals from the supervisory circuit through a scan circuit and when it receives a signal indicating that the handset has not been properly replaced. A howler tone source of a howler tone transmission circuit generates a low-level howler tone signal which is modulated by a modulator in the howler tone transmission circuit. This modulated tone signal is applied to a demodulator in the subscriber circuit through a speech connecting network for the transmission of speech to and from the telephone set without further need of connecting link such as a trunk line or the like. The telephone set converts the demodulated tone signal to a continuous howler tone audible signal.
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