Telephone interface protection circuit and modem using same
US5802151A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 16, 1996 |
| Grant date | Sep 1, 1998 |
| Priority date | — |
| Expiry date | Apr 16, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L43/0811
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A telephone interface protection circuit and modem incorporating the telephone interface protection circuit. The circuit includes a sensing circuit and a determining circuit. The interface protection circuit checks for an active telephone line and checks the line for over-current conditions caused when a modem designed for the public switched telephone network is plugged into a private digital telephone network. The circuit functions when the modem is operating to provide continuous monitoring. It can be built as a stand-alone device or incorporated into a modem. The circuit notifies the user of the line condition either with LEDs or with a status message sent to the user via the host computer interface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.