Programmable selective ringing circuit and method for party tele

Details Programmable selective ringing circuit and method for party tele Programmable selective ringing circuit and method for party tele

1986-10-21

1988-08-02

Levy, Stewart J.

Telephonic communications

Polystation line system

Call alerting

34082543, H04M 1300

Patent

active

047618108

ABSTRACT:
An apparatus and method for decoding ringing signals on a party telephone line coupled to the telephone line and a telephone instrument, according to the polarity of a d.c. voltage level present across the telephone line upon which ringing signals are superimposed and according to the grounded state of the telephone line. The apparatus comprises a discrimination circuit which supplies a selected one of the ringing signals to the telephone instrument via a ringing signal path to actuate the ringer of the telephone instrument. The apparatus further comprises a ringing signal rectification circuit connected to the telephone instrument via a voice signal path for preventing the ringing signal present on the telephone line from activating a ringer of the telephone instrument via the voice signal path. A switching circuit selectively connects the telephone instrument to the ringing signal path and the voice signal path. The apparatus further preferably comprises a circuit for eliminating bell taps and a balancing circuit for balancing the impedance across telephone line when the d.c. voltage level on the telephone line falls below a preset threshold, thereby forcing semiconductor devices on the line which could contribute to noise problems when only in a partly conductive state, into a conductive state, thereby eliminating the noise.

REFERENCES:
patent: 4587380 (1986-05-01), Curtin

Affiliated with

Also associated with

Rating

Programmable selective ringing circuit and method for party tele does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Programmable selective ringing circuit and method for party tele, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Programmable selective ringing circuit and method for party tele will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-715300