Telephonic communications – Centralized switching system – With generating of call associated substation signal
Patent
1986-09-08
1988-05-31
Schreyer, Stafford D.
Telephonic communications
Centralized switching system
With generating of call associated substation signal
379255, 379375, H04M 1902
Patent
active
047486597
ABSTRACT:
In a calling signal transmitting apparatus, a ring trip equipment, including a ring trip detecting circuit for detecting a ring trip signal in response to an off-hook operation of the telephone set during a signal state of an intermittent ringing signal and a loop detecting circuit for detecting a loop signal in response to an off-hook operation of the telephone set during a nonsignal state of the intermittent ringing signal. Also included are a logical OR gate circuit, for providing, as a status signal, a logical sum of the ring trip signal and the loop signal, and a supervising circuit for supervising the status signal. When an incoming call is being received by the telephone set, when the supervising circuit detects an off-hook state in the status signal, the supervising circuit stops the transmission of a ringing signal to the telephone set, and carries out a second supervising operation for supervising the status signal, and, if an on-hook state is detected during the second supervising operation, said supervising circuit again transfers the ringing signal to the telephone set.
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patent: 4496800 (1985-01-01), Young
Ayano Mitsutoshi
Iijima Yoshimi
Kasahara Kiyoshi
Miyazaki Yasuo
Nojiri Shoji
Fujitsu Limited
Schreyer Stafford D.
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