Interface circuits
US4292478A · kind A · utility
7Cited by
5References
30Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | May 25, 1979 |
| Grant date | Sep 29, 1981 |
| Priority date | — |
| Expiry date | May 25, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M19/001
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Interface circuitry is provided between a pair of lines, on the one hand, and an input to and output from other equipment on the other hand. The interface circuitry will commonly be used between `tip` and `ring` lines of a telephone connection and office telephone equipment but is not limited to the telephone art. The interface equipment provides independently controllable and adjustable impedances to `longitudinal` and transverse voltage changes on the pair of lines, means for transferring signals from the pair of lines to the output line and means for transferring signals from the input line to the pair of lines.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.