Telephonic communications – Call signal generating
Patent
1998-05-29
2000-12-26
Isen, Forester W.
Telephonic communications
Call signal generating
379252, 379373, 379375, H04M 900
Patent
active
061671355
ABSTRACT:
In generating a ringing signal of predetermined frequency and shape between the A- and B-wires to a subscriber's station in a telephone network, the ringing signal is directly injected in or superposed on the DC-levels of the wires. A voltage difference converting device converts any voltage difference between the A- and B-wires into a first current. A signal generating device generates a first voltage of the frequency and shape of the ringing signal to be generated, and a signal converting device then converts the first voltage into a second current. In a summation node the first current is subtracted from the second current to obtain a third current and this current is converted by passing it through a resistor to a second voltage. The second voltage is buffered and is again converted to a fourth current by applying the voltage to resistor. This fourth current is amplified by current amplifiers circuits comprising operational amplifiers, and is then supplied to the A-wire and drawn from the B-wire.
REFERENCES:
patent: 4220826 (1980-09-01), Kiss
patent: 4961219 (1990-10-01), Patel
patent: 5228081 (1993-07-01), Warner et al.
patent: 5260996 (1993-11-01), Dillon et al.
patent: 5307407 (1994-04-01), Wendt et al.
patent: 5323455 (1994-06-01), Le Corre
patent: 5490054 (1996-02-01), Hanebrink, Jr.
patent: 5553132 (1996-09-01), Randahl
patent: 5694465 (1997-12-01), Apfel
patent: 5734712 (1998-03-01), Randahl
patent: 5764755 (1998-06-01), Chen
patent: 5838788 (1998-11-01), Jakab
patent: 5872842 (1999-02-01), Daly et al.
Barkaro Stefan
Randahl Torbjorn
Wallin Berndt
Wiklund Sven
Isen Forester W.
Saint-Surin Jacques
Telefonaktiebolaget LM Ericsson
LandOfFree
Method and apparatus for generating a ringing signal 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 and apparatus for generating a ringing signal, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for generating a ringing signal will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1003718