Telephone answering device with direct telephone line interface
US5606598A · kind A · utility
3Cited by
21References
37Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Nov 24, 1992 |
| Grant date | Feb 25, 1997 |
| Priority date | — |
| Expiry date | Nov 24, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M1/654
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A telephone answering device with a direct telephone line connection eliminates the need for a transformer, optoisolators and relays that are normally used in telephone answering devices to isolate the telephone answering device system from the central office circuit. Isolation is instead achieved directly at the exposed metal points of the system by physical isolation, switched isolation, resistive isolation and dielectric isolation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.