Method of and circuitry for detecting, at a telephone exchange,

Details Method of and circuitry for detecting, at a telephone exchange, Method of and circuitry for detecting, at a telephone exchange,

1983-03-24

1985-07-09

Rubinson, Gene Z.

179 18FA, 179 84A, H04M 302

Patent

active

045284253

ABSTRACT:
In order to detect at an electronic telephone exchange the lifting of a subscriber's handset in response to ringing current sent over the line loop from a generator at that exchange, a charging current proportional to the incoming line current is fed to a capacitor over a recurrent integration period encompassing one or more whole ringing-current cycles. When the handset has been taken off the hook, the capacitor charge present at the end of such a period differs from zero on account of a d-c component superimposed upon the alternating ringing signal. In order to enable the use of a relatively small storage capacitor, the charging current is periodically interrupted by a train of chopping pulses. When the line current is measured at the exchange by a sensor responsive only to absolute magnitude, the polarity of the charging current is reversed in alternate nonzero-amplitude periods of a cycle.

REFERENCES:
patent: 4110569 (1978-08-01), Schindler et al.
patent: 4356355 (1982-10-01), Ferrieu et al.
patent: 4362908 (1982-12-01), Melindo
patent: 4396805 (1983-08-01), Wagner

Affiliated with

Also associated with

Rating

Method of and circuitry for detecting, at a telephone exchange, does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method of and circuitry for detecting, at a telephone exchange, , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of and circuitry for detecting, at a telephone exchange, will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-910611