Protection circuit for use with a telephone appliance and methods of use
US6088446A · kind A · utility
13Cited by
24References
26Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | May 6, 1998 |
| Grant date | Jul 11, 2000 |
| Priority date | — |
| Expiry date | May 6, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M1/745
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Protection circuitry for use with a modem is provided that detects excessive voltage between the tip and ring lines of a telephone subscriber loop when the modem is off-hook. When the over-voltage condition is detected, a switch is active, creating a circuit path that directs current away from the DC-holding circuit of the modem, thereby protecting the modem. The protection circuit of the present invention may be implemented using a minimal number of simple and inexpensive components.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.