Electronic trigger switch for maintenance termination unit
US4827497A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 21, 1988 |
| Grant date | May 2, 1989 |
| Priority date | — |
| Expiry date | Jul 21, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M3/301
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A telephone maintenance termination unit utilizes a low voltage, bidirectional trigger switch for performing diagnostic functions on a telephone line. The trigger switch provides low voltage, low current triggering in conjunction with a high holding current requirement. The trigger switch may comprise either two silicon controlled rectifiers connected in inverse parallel relationship with their gates connected, a bidirectional diffused PNPN semiconductor device, or an NPN semiconductor device, any one of which is used to trigger a power control TRIAC. In another embodiment, the switching device may be a two-terminal, unitary semiconductor device incorporating the functions of both the TRIAC and the bidirectional trigger switch.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.