Trunk adapter
US4002850A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 25, 1975 |
| Grant date | Jan 11, 1977 |
| Priority date | — |
| Expiry date | Mar 25, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q3/625
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A trunk adapter is associated with a common control private automatic branch exchange telephone system for interfacing the system with a central office. Four different types of adapters are associated with the system to effect a ring-down incoming, loop start outgoing trunk connection, a ground start type trunk connection, a two-way dial-to-dial trunk connection, and a two-way E and M signalling interface. To provide a buffer between the ring and tip circuits the adapters employ optical coupler circuits. The adapters are controlled by the common control on a time shared basis and operate independently of the state of the sleeve lead.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.