Telephone switch hook interface circuit
US5859906A · kind A · utility
3Cited by
16References
13Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Nov 19, 1996 |
| Grant date | Jan 12, 1999 |
| Priority date | — |
| Expiry date | Nov 19, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M1/82
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A switch hook interface circuit couples a subscriber telephone to a subscriber telephone line. This interface circuit comprises a source of an off-hook signal, having one state indicating an off-hook condition, and a second state indicating an on-hook condition. A circuit is coupled between the off-hook signal source and the subscriber telephone line which gradually increases the current drawn from the subscriber telephone line when the off-hook signal indicates an off-hook condition, and gradually decreases the current drawn from the subscriber telephone line when the off-hook signal indicates an on-hook condition.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.