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Patent Searching and Data


Title:
HOOK DETECTOR FOR TELEPHONE SET
Document Type and Number:
Japanese Patent JPH05110648
Kind Code:
A
Abstract:

PURPOSE: To prevent an output of an error signal by providing an inaudible sound wave generating circuit to the detector, providing a sound collection device collecting the sound wave to the handset, and detecting the hook state based on a level of a signal outputted from the sound collection device.

CONSTITUTION: With a handset 7 loaded to a telephone set main body 1, since a sounding body 6 and a sound collection device 8 are close to each other, a level of a signal collected by a sound collection device 8 exceeds a reference level set to a hook detection circuit 10. Thus, since a detection signal representing on-hook is outputted from the circuit 10 to a telephone set circuit 3, the circuit 3 receiving the signal keeps the on-hook state. On the other hand, when the handset 7 is lifted up and a sounding body 6 and the sound collection device 8 are parted, the level of the signal collected by the sound collection device 8 is reduced more than the reference level. Thus, since a detection signal representing the off-hook is outputted from the circuit 10 to the circuit 3, the circuit 3 receiving it is connected to the telephone line 2.


Inventors:
YOSHIDA SETSU
Application Number:
JP26479491A
Publication Date:
April 30, 1993
Filing Date:
October 14, 1991
Export Citation:
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Assignee:
SHARP KK
International Classes:
H04M1/06; (IPC1-7): H04M1/06
Attorney, Agent or Firm:
倉内 義朗