Protection arrangement for a telephone subscriber line interface

Details Protection arrangement for a telephone subscriber line interface Protection arrangement for a telephone subscriber line interface

1985-06-20

1987-11-24

Pellinen, A. D.

Electricity: electrical systems and devices

Safety and protection of systems and devices

With specific current responsive fault sensor

361 91, 361 93, 361119, 361 7, 361 5, 361 6, 379412, 379413, H04M 318, H02H 3093

Patent

active

047092963

ABSTRACT:
The contacts of an isolation relay are positioned between a line interface circuit and the associated feed resistors, the relay being controlled to open the contacts in response to an excessive common mode alternating current through the feed resistors. The common mode a.c. is detected by a sensing amplifier, and is integrated and compared with a threshold level in a dectector unit. If the common mode a.c. is excessive, a zero crossing predictor enables the detector unit to control the isolation relay and open its contacts at a zero crossing of the a.c. A phase shifter in the zero crossing predictor compensates for the response delay of the isolation relay. As the excessive current is now interrupted, the sensing amplifier responds to the line voltage. When this falls below a predetermined peak level, a delayed resetting of the protection arrangement is automatically effected.

REFERENCES:
patent: 3671807 (1972-06-01), Milligan
patent: 3808455 (1974-04-01), Leisi
patent: 4197435 (1980-04-01), Jackson
patent: 4431868 (1984-02-01), Bolus et al.
patent: 4431869 (1984-02-01), Sweet
patent: 4467310 (1984-08-01), Jakab

Affiliated with

Also associated with

Rating

Protection arrangement for a telephone subscriber line interface does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Protection arrangement for a telephone subscriber line interface, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Protection arrangement for a telephone subscriber line interface will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2425123