The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 22, 1991
Filed:
Nov. 03, 1989
Jacques Allouis, Ostwald, FR;
Patrick Hauptmann, Strasbourg, FR;
Xavier Penet, Illkirch Graffenstaden, FR;
Pierre Saint-Ellier, Strasbourg, FR;
Telic Alcatel, Paris, FR;
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.