Telephone line interface circuit

Details Telephone line interface circuit Telephone line interface circuit

1995-04-10

1997-05-06

Matar, Ahmad F.

Telephonic communications

Subscriber line or transmission line interface

379413, H04M 158, H04M 1900

Patent

active

056278900

ABSTRACT:
In a telephone line interface circuit, a first transistor (Q1) is arranged in series in the signal line (3) and a second transistor (Q2) is arranged in parallel across the telephone line (3, 4), both transistors being controlled from a control circuit (5), so that, when the voltage across the telephone line falls below that required to keep the first transistor (Q1) in normal conduction, the second transistor (Q2) maintains the signal path. In order to reduce cross-over distortion, a negative feedback loop (Q5, R1, Q3, Q1) and supply voltage sensing means (6) controls the first transistor (Q1) so that it conducts only sufficient quiescent current to power the circuit, any remaining current being conducted by the second transistor (Q2), thereby maintaining both transistors in conduction down to low quiescent line current levels.

REFERENCES:
patent: 4309574 (1982-01-01), Sublette et al.
patent: 4748664 (1988-05-01), Blomley
patent: 4796295 (1989-01-01), Gay et al.
patent: 4953207 (1990-08-01), Van Dongen et al.
patent: 5239579 (1993-08-01), Schuh
patent: 5384842 (1995-01-01), Tapping et al.

Affiliated with

Also associated with

Rating

Telephone line interface circuit 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 line interface circuit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Telephone line interface circuit will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2138701