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 c ould present itself if there is a link p roblem to
the EPN, and the EPN experiences several EPN restarts. The Maintenance
circuit pack ma y be reinstalled after the Expansion Interfac e circuit pack
has been physically inserte d and the Expansion Interface circ uit pack’s red
LED has gone off.
The link between two Active Expansion Interfac e circuit packs or b etween an
Active Expansion Interface c ircuit pack and an A ctive Switch Node Interface
circuit pack is involved in synchronization. The Expansion Interfac e circuit pac k
will report slip errors if synch ronization is not operating proper ly. When
diagnosing sync hronization problems, the Expansion Interfac e circuit packs
should be examined as a possible cause.
EI and Tone-Clock Interactions
The viability of the EI fiber link depend s upon the system clock that is provided
by the active Tone-Clock circuit p ack on each network (see “TDM-CLK” an d
“TONE-BD” documentation). Each Expansion Interface circuit pac k transmits
over the fiber at a rate derived from the system c lock on its network. If the Active
Tone-Clock is defective in such a way that the freq uency of system clock it
produces is out of the sp ecified range (“ out of spec”), an Expansion Inter face
fiber link might go d own. This affects an Expansion Archangel Link (EAL), a
Remote Neighbor Link (RNL), and/or a Local Ne ighbor Link (LNL), even though
the Expansion Interface circu it packs are healthy. When the PNC is duplicated,
both fiber links could go down if there is a defec tive Active Tone-Clock. Whether
or not a fiber link goes down, d epends on certain characteristics of the
Expansion Interface circuit p acks. An Expansion Interface c ircuit pack should no t
be replaced if the fib er link on which it resides goes do wn because of a defective
Active Tone-Clock circuit pack . The defective Tone-Clock circuit pack sho uld be
replaced instead . The Expansion Interface circuit pac ks are more sensitive to a
defective system cloc k than the rest of the components of the system. Therefore,
testing of the Tone-Clock circuit pac k might not reveal a problem.
The symptoms of the problem in whic h an invalid system cloc k 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 cloc k :
Any Expansion Interface or SNI circuit p ack has a Fiber Out-of-Frame
condition or a No Neighb or condition.
An Expansion Interface circ uit pack yellow LED blinks quic kly when a
Fiber Out-of-Frame condition exists (0.1 sec onds on, 0.1 seconds off) and
Test #238 fails on the Expansion Interface circuit pac k that is out-of-frame.
An SNI circuit pack with a Fiber Out-of-Frame condition blinks its yellow
LED quickly (0.1 seconds o n, 0.1 seconds off) and Test #989 fails on the
SNI circuit pack that is out-of-frame.