DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126
Issue 4
June 1999
Maintenance Object Repair Procedures
9-792EXP-INTF (Expansion Interface Circuit Pack)
9
pack reset. This condition could present itself if there is a link problem to
the EPN, and the EPN experiences several EPN restarts. The Maintenance
circuit pack may be reinstalled after the Expansion Interface circuit pack
has been physically inserted and the Expansion Interface circuit pack’s red
LED has gone off.
The link between two Active Expansion Interface circuit packs or between an
Active Expansion Interface circuit pack and an Active Switch Node Interface
circuit pack is involved in synchronization. The Expansion Interface circuit pack
will report slip errors if synchronization is not operating properly. When
diagnosing synchronization problems, the Expansion Interface circuit packs
should be examined as a possible cause.
EI and Tone-Clock Interactions
The viability of the EI fiber link depends upon the system clock that is provided
by the active Tone-Clock circuit pack on each network (see “TDM-CLK” and
“TONE-BD” documentation). Each Expansion Interface circuit pack transmits
over the fiber at a rate derived from the system clock on its network. If the Active
Tone-Clock is defective in such a way that the frequency of system clock it
produces is out of the specified range (“out of spec”), an Expansion Interface
fiber link might go down. This affects an Expansion Archangel Link (EAL), a
Remote Neighbor Link (RNL), and/or a Local Neighbor Link (LNL), even though
the Expansion Interface circuit packs are healthy. When the PNC is duplicated,
both fiber links could go down if there is a defective Active Tone-Clock. Whether
or not a fiber link goes down, depends on certain characteristics of the
Expansion Interface circuit packs. An Expansion Interface circuit pack should not
be replaced if the fiber link on which it resides goes down because of a defective
Active Tone-Clock circuit pack. The defective Tone-Clock circuit pack should be
replaced instead. The Expansion Interface circuit packs are more sensitive to a
defective system clock than the rest of the components of the system. Therefore,
testing of the Tone-Clock circuit pack might not reveal a problem.
The symptoms of the problem in which an invalid system clock causes an
Expansion Link to go down are as follows:
■ If the Tone-Clock in the PPN, or in an EPN that provides the current on-line
synchronization reference (see
status synchronization
), is providing an
invalid system clock:
Any Expansion Interface or SNI circuit pack has a Fiber Out-of-Frame
condition or a No Neighbor condition.
An Expansion Interface circuit pack yellow LED blinks quickly when a
Fiber Out-of-Frame condition exists (0.1 seconds on, 0.1 seconds off) and
Test #238 fails on the Expansion Interface circuit pack that is out-of-frame.
An SNI circuit pack with a Fiber Out-of-Frame condition blinks its yellow
LED quickly (0.1 seconds on, 0.1 seconds off) and Test #989 fails on the
SNI circuit pack that is out-of-frame.
