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Method and apparatus for sparing communications circuits
| Details |
Inventors: Lynch, Franklin A.;
Assignee: Nortel Networks Limited (St. Laurent, CA)
Primary Examiner: Deane, Jr.; William J.
Assistant Examiner:
Attorney, Agent or Firm: Withrow & Terranova, PLLC
Splitting circuitry receives external telecommunications lines and splits them into corresponding primary and secondary lines for implementing an N:l sparing arrangement in an associated telecommunications system. Sparing circuitry receives the secondary lines and includes selection circuitry and a sparing bus, where the selection circuitry selectively connects a desired group of secondary lines to the sparing bus in response to a selection control signal. Preferably, the telecommunications system routes communications traffic between subscriber equipment connected via the external telecommunications lines and a larger communications network using N primary line interfaces coupled with the primary lines. When desired, the telecommunications system controls the sparing circuitry such that secondary lines corresponding to a group of primary lines associated with a given primary line interface connect to the spare line interface. Thus, communications traffic that would otherwise be routed through the given primary line interface is routed through the spare line interface. Because sparing functions associated with the secondary signals do not interfere with primary signals, maintenance and service operations may be performed on elements of the sparing circuitry without interrupting data traffic being carried on the primary lines. This is particularly advantageous for telecommunications systems having primary line interfaces that support a large number of telecommunication lines, where removing even a single primary line interface from service for sparing equipment maintenance is unacceptable. |
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DETAILED DESCRIPTION The present invention splits telecommunication lines, such as DS1 subscriber lines, into primary and secondary signal paths within a piece of telecommunications line interface equipment.
The primary signal paths connect the telecommunication lines to primary interface circuits, while the secondary signal paths are used to selectively connect desired ones of the telecommunication lines to spare interface circuits as needed.
Preferably, the present invention includes a switching network that operates only on the secondary signal paths to connect selected ones of the telecommunication lines to the spare interface circuits.
As such, the telecommunication lines remain connected to the primary line interfaces through the primary signal paths, which are independent of the switched secondary signal paths used with the spare line interface circuits.
This allows maintenance to be performed on the switching network or on the spare line interface circuits without disrupting services on any of the telecommunication lines supported by the primary interface circuits.
Preferably, the present invention includes circuitry for splitting incoming telecommunication lines into corresponding primary and secondary lines, and operating on the secondary lines to implement sparing functions.
The primary lines couple directly to the primary line interfaces through the primary signal paths and are not routed through the sparing circuitry operating on the secondary lines.
The sparing circuitry may include sparing switches (switching network) and associated control circuitry for selectively connecting desired ones of the secondary signal paths to a spare line interface.
Preferably, the sparing circuitry is configured as a backplane, sparing switch cards, and a sparing switch control card.
The backplane connects a group of secondary signals to each sparing switch card, and each sparing switch card includes switched connections for selectively connecting its associated group of secondary signals to a sparing bus carried on the backplane
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Cell Phones 
