Telephone ring detector
US5544241A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 27, 1995 |
| Grant date | Aug 6, 1996 |
| Priority date | — |
| Expiry date | Jun 27, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/32795
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A telephone ring detector detects a ring signal voltage from a diverse set of signals transmitted on a telephone line before a complete alternating current ring signal cycle is received. In an exemplary embodiment, the ring detector includes a voltage threshold setting device for establishing a voltage threshold and comparing the ring signal voltage to the voltage threshold to provide an output signal when the ring signal voltage is above the voltage threshold. A pair of zener diodes having a selected voltage value can provide the threshold setting and comparison functions. A microprocessor, including a timer for measuring a time duration of the output signal, outputs a ring detection signal when the time duration exceeds a predetermined time interval value, which is substantially less than a full ring cycle. A line switch responsive to the ring detector is provided to direct communication signals to a telecommunications device.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.