Integrated ring sensor with fault detection
US5809109A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 1, 1995 |
| Grant date | Sep 15, 1998 |
| Priority date | — |
| Expiry date | Jun 1, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M3/02
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A power cross circuit detects a ring trip condition in order to switch a pair of switch relays to a protection circuit and to appropriate line driver circuitry to enable a talking condition for a telephone. The power cross circuit detects a rise in a DC current across a feed resistor connected to a ring bus and a ring line. The power cross circuit determines a difference in current passing across a first and second sense amplifier connected to respective ends of the feed resistor. The current difference is then converted to a voltage difference, and utilized by the power cross circuit to output a power cross condition when the current difference exceeds a predetermined value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.