Telecommunications off-hook and intrusion detection method and apparatus
US6470083B1 · kind B1 · utility
4Cited by
20References
67Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 24, 1997 |
| Grant date | Oct 22, 2002 |
| Priority date | — |
| Expiry date | Dec 24, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M1/82
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A method and apparatus to detect off-hook and intrusion conditions on a telephone line. A voltage to frequency converter is used to convert the voltage measured between the TIP and RING terminals of a telephone line to a frequency. The voltage is continuously monitored, once during each sample period. The measured frequency is compared to predetermined threshold values to determine the state of the telephone line. The predetermined threshold values are updated in each sample period.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.