1977-08-29
1979-03-20
Cooper, William C.
179 84R, H04M 304
Patent
active
041455770
ABSTRACT:
A ringing control apparatus comprises a bidirectional switching circuit connected in series to a ringing source, which generates an alternating current of a large amplitude, for delivering to a called subscriber the AC signal as an interrupted ringing signal, a phase detector circuit in the form of a zero level detector for detecting the phase of the AC signal generated from the ringing source, and a control circuit for generating a signal for turning on and off the switching circuit in synchronism with the output signal of the phase detector circuit. The delivery of the ringing to the called subscriber is started at a point of time when the ringing voltage comes to a zero level and is stopped at a point of time when the ringing current comes to a zero level, thereby to prevent generation of a surge voltage.
REFERENCES:
patent: 3551604 (1970-12-01), Joel
IBM Technical Disclosure Bulletin, vol. 12, No. 11, Apr. 1970, pp. 1759-1761, "Ringing System for Telephone Lines".
IBM Technical Disclosure Bulletin, vol. 12, No. 11, Apr. 1970, pp. 1736-1737, Garcia, J., "Ringing System for Telephone Lines".
Kojima Takafumi
Miyoshi Tatsuru
Mukaemachi Takuji
Cooper William C.
Hitachi , Ltd.
Popek Joseph A.
LandOfFree
Ringing control apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ringing control apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ringing control apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-222508