Remotely activated switching apparatus
US4807277A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 15, 1987 |
| Grant date | Feb 21, 1989 |
| Priority date | — |
| Expiry date | May 15, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M3/301
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Apparatus for disconnecting and reconnecting equipment to a telephone line in response to a signal sent over the telephone line. The apparatus includes a voltage threshold circuit, a voltage regulator circuit and a switching and timing circuit. The switching and timing circuit includes a first energy storage capacitor and a first discharge circuit. The switching and timing circuit further includes a second energy storage capacitor and a second discharge circuit and further includes a third energy storage capacitor and timing resistor. The first discharge circuit includes a first semiconductor switching device and a relay coil of a latching relay. The second discharge circuit includes a second semiconductor switching device and a second relay coil of the latching relay. When a signal is sent over the telephone line which exceeds the threshold level, it is regulated by the voltage regulator and charges up the first, second and third storage capacitors in an order such that the third capacitor charges first, the second capacitor next and the first capacitor last. Once the signal disappears from the telephone line, the first storage capacitor discharges into the first discharge circuit…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.