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.

Date of Patent:
Dec. 02, 2003

Filed:

Jul. 11, 2000
Applicant:
Inventors:

Colin Bell, Acton, MA (US);

Mike A. Sluyski, Maynard, MA (US);

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G06F 1/12 ;
U.S. Cl.
CPC ...
G06F 1/12 ;
Abstract

The present invention provides a network device including redundant, synchronous central timing subsystems (CTSs) each having a voltage controlled timing circuit for receiving a constant master voltage signal and variable slave voltage signal. Each CTS also includes a control logic circuit for selecting the constant master voltage signal for use by the voltage controlled timing circuit when the CTS is master and for selecting the variable slave voltage signal when the CTS is slave. Using a constant master voltage signal eliminates the need for a separate master oscillator in each CTS. Oscillators are typically expensive, consume significant space on the printed circuit board and have location restrictions on where they may be placed on the printed circuit board.


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