Telephone subscriber line voltage change detection

Details Telephone subscriber line voltage change detection Telephone subscriber line voltage change detection

1990-12-20

1994-02-15

Dwyer, James L.

Telephonic communications

Supervisory or control line signaling

Using line or loop condition detection

307358, 379380, 379382, H04M 322, H03K 524

Patent

active

052874044

ABSTRACT:
Changes in a telephone subscriber line voltage are detected in a telephone set by supplying a voltage dependent upon the subscriber line voltage to a potential divider having first, second, and third tapping points, the second tapping point being between the first and third tapping points, and comparing the voltages at the first and third tapping points with a smoothed version of the voltage at the second tapping point to produce pulses at respective terminals when the line voltage is falling or rising. An algorithm is described for responding to the pulses to distinguish changes in hook state of another telephone connected to the same subscriber line from interfering signals. The arrangement facilitates remote release from hold and privacy indication functions for the telephone set.

REFERENCES:
patent: 3955102 (1976-05-01), Chi
patent: 3991376 (1976-11-01), Stevens
patent: 4132864 (1979-01-01), Feng
patent: 4193028 (1980-03-01), Downs, II
patent: 4319092 (1982-03-01), Van der Enden et al.
patent: 4446338 (1984-05-01), Rosch
patent: 4540853 (1985-09-01), Albouy
patent: 4674118 (1987-06-01), Tosto
patent: 4761566 (1988-08-01), Inoue et al.
patent: 4802207 (1989-01-01), Uchida
patent: 4823227 (1989-04-01), Grant
patent: 4859872 (1989-08-01), Hyakutake
patent: 4899379 (1990-02-01), Vaclavik
patent: 4939471 (1990-07-01), Werrbach
patent: 5047751 (1991-09-01), Miura et al.
patent: 5159340 (1992-10-01), Smith
Radio Shack; Linear Applications vol. I; Nov. 1967; p. AN74-5.

Affiliated with

Also associated with

Rating

Telephone subscriber line voltage change detection does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Telephone subscriber line voltage change detection, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Telephone subscriber line voltage change detection will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1213651