Ringer system for a telephone
US4374307A · kind A · utility
2Cited by
2References
3Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Aug 29, 1980 |
| Grant date | Feb 15, 1983 |
| Priority date | — |
| Expiry date | Aug 29, 2000 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M19/04
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A telephone ringer system is disclosed which uses an oscillator circuit to drive a piezoelectric transducer to produce the ring signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.