Method and apparatus for determining when a telephone handset is off-hook
US4958371A · kind A · utility
62Cited by
29References
5Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 19, 1988 |
| Grant date | Sep 18, 1990 |
| Priority date | — |
| Expiry date | Apr 19, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M11/06
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Apparatus in an automatic telecommunications system which communicates between a central location and at least one remote location over the switched telephone network, senses changes in loading of the telephone line which correspond to a telephone going off-hook, to serve as an indication that a telephone has gone off-hook and to cause the automatic telecommunications system to relinquish its use of the telephone line, or not to go off-hook if a telephone is in use.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.