Semiconductor subscriber line interface circuit with enhanced su

Details Semiconductor subscriber line interface circuit with enhanced su Semiconductor subscriber line interface circuit with enhanced su

1987-11-13

1989-08-08

Dwyer, James L.

Telephonic communications

Subscriber line or transmission line interface

Protective circuit

379399, 379413, 361106, 361119, H04M 174

Patent

active

048560596

ABSTRACT:
A subscriber line interface circuit using integrated semiconductor circuit is provided with improved immunity to overvoltage and overcurrent conditions by increasing value of the battery feed resistors in series circuit with the ring and tip lines to increase the impedance encountered by a lightning-induced voltage spike to increase the survivability of the semiconductor circuit components. The battery supply voltage is increased to effect a commensurate increase in loop current, and the loop impedance is re-adjusted by appropriately configured operational amplifiers. A thermally responsive sensor is mounted in a heat-conducting relationship with resistive elements in the subscriber loop with an increase in temperature representing an overcurrent situation, such as power line cross-over, and provides a control signal effective to disconnect the subscriber loop from interface circuit.

REFERENCES:
patent: 4477857 (1984-10-01), Crocker
patent: 4563547 (1986-01-01), Booth
patent: 4661979 (1987-04-01), Jakab
patent: 4709296 (1987-11-01), Hung et al.
Harris Corporation. "Subscriber Line Interface Circuit", HC5509, Feb. 1987 (Preliminary).
Harris Corporation App Note No 549, "The HC-550X Telephone Subscriber Line Interface Circuits (SLIC)", Phillips, Geoff.
Midwest Components, Inc. Product Data, "Section: 4007 Poly PTC Current Protector".

Affiliated with

Also associated with

Rating

Semiconductor subscriber line interface circuit with enhanced su does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Semiconductor subscriber line interface circuit with enhanced su, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Semiconductor subscriber line interface circuit with enhanced su will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-912064