Adaptive no balance DX signalling circuit
US5247574A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 19, 1990 |
| Grant date | Sep 21, 1993 |
| Priority date | — |
| Expiry date | Jul 19, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q1/30
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
The no balance duplex signalling circuit eliminates the need for setting balance resistors and capacitors to match or be proportional to cable resistance and capacitance as was required of previous duplex signalling circuit designs. A microcomputer is also used to evaluate the output of a simple loop current and voltage sensing circuit to dynamically determine the signalling state of the far end of the trunk conductors. The microcomputer stores a plurality of data which indicate signalling thresholds for all possible duplex signalling states. The microcomputer can then compare the measured voltage and current on the trunk conductors to automatically make a determination of the signalling state based on the stored data indicative of permissible signalling states.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.