Telephone instrument circuit
US4608462A · kind A · utility
16Cited by
1References
6Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Oct 19, 1984 |
| Grant date | Aug 26, 1986 |
| Priority date | — |
| Expiry date | Oct 19, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M9/085
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An integrated circuit for a telephone instrument provides the basic (POT) service requirement. The transmit and receive channels of the circuit may be fed via controlled attenuators incorporated in a first ancillary circuit to provide hands-free operation. The circuit also includes a current-limited power supply whereby connection to a second ancillary circuit, including an audio amplifier, may be effected to provide loudspeaker operation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.