Synchronizing system for a private digital exchange connected to an
US5060241A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 3, 1989 |
| Grant date | Oct 22, 1991 |
| Priority date | — |
| Expiry date | Nov 3, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q11/0428
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A synchronizing system for a private digital exchange (1) comprising a logic control unit (4) and specialized interfaces (9, 8) whereby the exchange is connected firstly to a plurality of subscriber terminals (2) via SO accesses, and secondly to a telecommunications network (3) via TO base accesses. The exchange includes a time base (6) which associates a fixed frequency local oscillator (7) with a phase locked loop (32). The system includes clock switching means suitable for imposing the first clock signals to come from the network (3) via an active one of the TO base accesses and the associated interface (8) on the phase locked loop (32) of the time base (6) as soon as said first clock signals come close in phase to the substitute clock signals provided by the time base (6) in the absence of said first signals from the network.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.