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097-55501-01 Issue 6 – June 2003 51
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Description
alarms detected are:
- Shelf Power A or B not detected. This will illuminate the Alarm
LED as well as appropriate Shelf Power LED (red). Associated
TL1 events are EXPWRA and EXPWRB (Expansion Power Fail
on terminal A or B).
- Problem with Link A or Link B. See detailed description in item
below on expansion link LEDs.
- The expansion controller card is receiving a good link but it is
not associated with its "preferred" master shelf clock.
The concept of a "preferred" clock is used to better support
redundancy. The idea is that during normal operation each
expansion controller card will be taking its clock from a
different clock card. However, an expansion controller card is
able to take its clock from either clock card so it is not critical
that an EC card get its clock from its preferred source. This
alarm is reported simply to indicate the situation when this
card is currently not getting its clock from the preferred
source. Specifically:
> An EC card inserted into the EC1 (leftmost) slot "prefers" to
take its clock from CLK1 (leftmost clock card on master
shelf). If it is only able to get a valid link by using CLK2, the
alarm LED will light.
> An EC card inserted into the EC2 (rightmost) slot "prefers" to
take its clock from CLK2 (rightmost clock card on master
shelf). If it is only able to get a valid link by using CLK1, the
alarm LED will light.
The preference association is easy to remember by realizing
that the leftmost clock card and leftmost EC card are a
preferred pair while the rightmost clock card and rightmost
EC card are a preferred pair.
• Fail LED. This will be red if the card experiences a failure condition
(e.g., the card cannot power-up successfully).
• Shelf Power A, B LEDs. These LEDs provide indication of
expansion shelf power status. Green indicates that power is being
successfully supplied to the associated shelf power terminal (A or
B). Red indicates that power is not being successfully supplied to
the associated power terminal.
• Expansion Links 1, 2 LEDs. These LEDs indicate status of the
cable links that connect the master shelf to this expansion shelf.
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