Ring-trip detector
US4262172A · kind A · utility
6Cited by
4References
10Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Jan 17, 1980 |
| Grant date | Apr 14, 1981 |
| Priority date | — |
| Expiry date | Jan 17, 2000 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M19/026
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A ring-trip detection circuit is disclosed which is suitable for use at the remote terminal of a pair gain system, i.e., a system designed to supply more than one telephone subscriber with loop service over a single pair of metallic wires. The ring-trip detector circuit comprises a simple filter and semiconductor threshold circuit which responds to subscriber loop currents to disable ringing signals when the subscriber goes off-hook. The detector circuits are powered entirely by the ringing signal itself and thus draw no power when in the inactive state and require no auxiliary powering source in the active state.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.