Telephone set with loop current interruption timing control
US4086440A · kind A · utility
5Cited by
2References
12Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Apr 12, 1977 |
| Grant date | Apr 25, 1978 |
| Priority date | — |
| Expiry date | Apr 12, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M1/53
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
In a telephone set, possible mistakes in the generation of "hook flash" and "disconnect" signals, as customarily produced by operation of the hook switch and manifested as interruptions in the loop current, are avoided by a signal generating circuit which produces an accurately timed interruption of loop current, as a hook flash signal, in response to operation of a hook flash push button and which also produces another accurately timed and substantially longer interruption of loop current, as a disconnect signal, in response to operation of the hook switch.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.