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DEFINITY Enterprise Communications Server Release 5
Maintenance and Test for R5vs/si
555-230-123
Issue 1
April 1997
Reliability Systems: A Maintenance Aid
Page 6-6Duplicated Hardware
6
follows: Processor A to Maintenance/Tape Processor A over the serial link to
Duplication Interface A over the serial link to Maintenance/Tape Processor B to
Processor B. The flow in the reverse direction is exactly opposite.
The serial link between Duplication Interface A and Duplication Interface B is
involved only in memory shadowing from the Active SPE to the Standby SPE as
described in the ‘‘
Memory Shadowing’’ section.
SPE Select Switches
The SPE-SELEC (SPE Select) switches are located on the TN772 Duplication
Interface circuit packs and are used to hard-select the Active SPE in a high or
critical reliability system. “Hard-select” means that the SPE Select switches can
be moved from the AUTO position to force the current Active SPE to remain the
Active SPE or to force the current Standby SPE to become the Active SPE. Hard
selection of the Active SPE using the SPE Select switches overrides any attempts
by the system software to switch to the Standby SPE to make it become the
Active SPE.
Each switch has three positions:
■ SPE-A (the left position)
■ AUTO (the middle position)
■ SPE-B (the right position)
To hard-select SPE A as the Active SPE,
both
SPE Select switches must be
moved one at a time to the SPE-A position. To hard-select SPE-B as the Active
SPE,
both
SPE Select switches must be moved to the SPE-B position. Any other
combination of SPE Select switches leave control of the Active SPE to the system
software.
Inter-Cabinet Cable
As described previously, the ICC connects the two TN772 Duplication Interface
circuit packs and is a basis of support for the Duplication Interface circuit pack
functionality described previously.
The ICC carries leads related to maintaining a High or Critical Reliability system.
The SPE Select lead indicates which SPE is the Active SPE. The Tone-Clock
Select leads indicate which Tone-Clock circuit pack is active. SPE Select switch
state leads indicate the position of the SPE Select switches. Emergency Transfer
leads indicate whether Emergency Transfer is on or off in the PPN cabinet. Other
leads “combine” the INADS, CDR, and the Customer-Provided Alarming device
channels from the two Maintenance/Tape Processors.
The ICC also carries an indication of whether memory shadowing is enabled or
disabled. Information to be shadowed is sent over the serial link between