Switching arrangement for monitoring polarity reversal on lines in telecommunication systems
US4092489A · kind A · utility
3Cited by
4References
3Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Mar 30, 1977 |
| Grant date | May 30, 1978 |
| Priority date | — |
| Expiry date | Mar 30, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q3/00
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Apparatus is described for monitoring the state, e.g., with regard to polarity, of signal lines in a telecommunication system. An input circuit, by means of high resistances relative to the line resistance, connects the lines to a differential amplifier having a predetermined threshold of response. A component of the amplifier output is applied to the input so as to have a polarity opposite to that of a bias voltage coupled to the amplifier. A capacitive protective circuit connected between the signal lines provides a time delay thereby protecting against interference pulses.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.