Patent
1976-05-06
1977-07-19
Claffy, Kathleen H.
179 84SS, 179 18AD, 179 37, H04M 906
Patent
active
040370585
ABSTRACT:
A control circuit including a mechanical interrupter provides a plurality of interrupted ringing signal bursts when one of a plurality of intercom stations goes off-hook and first initiates a call to another of the plurality of intercom stations. The interrupter also provides an interrupted voltage to cause a button lamp at the another of the plurality of intercom stations to flash. A call selector circuit and a call routing circuit are coupled to the control circuit and the plurality of intercom stations to provide a connection between the one and the another of the plurality of intercom stations to enable the interrupted ringing signal bursts to be conducted on the connection to the another of the plurality of intercom stations. Logic circuitry is coupled to the plurality of intercom stations and the control circuit to detect when the one and the another of the plurality of intercom stations are both off-hook. When this condition is detected the interrupted ringing signal bursts are stopped and the button lamp is caused to glow steadily.
REFERENCES:
patent: 3014097 (1961-12-01), Apt
patent: 3406260 (1968-10-01), McEowen
patent: 3524931 (1970-08-01), Cartwright et al.
patent: 3725594 (1973-04-01), Cartwright et al.
patent: 3739100 (1973-06-01), Cartwright
patent: 3909551 (1975-09-01), Marshall
Brigance Gerald L.
Claffy Kathleen H.
Hill Alfred C.
International Telephone and Telegraph Corporation
O'Halloran John T.
LandOfFree
Intercom system for a key telephone system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Intercom system for a key telephone system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Intercom system for a key telephone system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2294405