Telephone subscriber system incorporating a drive interface for a telephone line switch at a different reference potential
US5461670A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 30, 1993 |
| Grant date | Oct 24, 1995 |
| Priority date | — |
| Expiry date | Dec 30, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M1/738
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A telephone subscriber system comprising a speech circuit and a ring circuit adapted to be integrated monolithically to a semiconductor material substrate and being coupled to a telephone subscriber line, respectively through first and second circuit switch of the diode bridge type, further comprises a first circuit changeover switch, under control by the user, which drives at least second and third circuit switching means connected between the first diode bridge circuit and the speech circuit. The third circuit changeover switch is connected to the speech and ring circuits at a circuit communication node which forms the system point of reference, physically coincident with the substrate. The system includes a circuit interface means for controlling the second and third circuit changeover switch by external electrical signals which are related to the circuit communication node. The circuit interface circuit comprises a diode connected with its cathode to the circuit communication node, in parallel with the third circuit changeover switch.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.