Telephone system with multiple extension telephones
US5090052A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 9, 1991 |
| Grant date | Feb 18, 1992 |
| Priority date | — |
| Expiry date | Apr 9, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M9/027
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An improved telephone system in which a plurality of telephone units connected to a common telephone line is directly connected to an outside telephone line. Each telephone unit contains complete capability for making outside calls, for making extension calls, and for the automatic exchange control of the use of the common telephone line. This telephone system provides functions, including making multiple simultaneous calls on a single telephone line without requiring separate exchange equipment, additional extension or signal lines, or any sacrifice in signal quality. Furthermore, the telephone units in this system can be connected to more than one outside telephone line to expand the system capacity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.