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US 4,349,703 AGranted
Programmable ring signal generator
AssigneeInternational Telephone and Telegraph Corporation
InventorRamon C. W. Chea, Jr.
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Abstract
The present invention comprehends an improved ringing circuit particularly suitable for digital telecommunications systems wherein the energizing and de-energizing of the ring circuitry is programmably controlled to provide for either hardware or software generation of ringing cadence, dc bias polarity, dry-switching of ring relays, and other signaling voltages. Further in accordance with the invention, a digital implementation of a complete ringing circuit is achieved without the use of bulky transformers.
Claims12
A digitally controlled ring signal generator comprising:
- ring signal generation circuit means for selectively amplifying at least a plurality of multi-frequency ringing signals for providing immediate ringing to one or more subscriber lines;
- loop current sensing means for sensing loop current;
- ring supervision circuit means responsive to said loop current sensing means for generating ringing supervisory signals;
- ring circuit control logic means responsive to said ringing supervisory signals and to an external data input, for generating an output control signal;
- and
- a ring signal reference source for coupling multi-frequency ringing signals to said ring signal generation circuit means in response to said output control signal, such that the characteristics of said ringing signals are selectable in accordance with said external data input and the presence or absence of the generated ringing signals is determined by said ringing supervisory signals.
3 more elements
Dependencies are inferred from the claim text.