DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126 Issue 4
June 1999
Maintenance Object Repair Procedures
9-1781TONE-BD (Tone-Clock Circuit Pack)
9
Manual EPN Tone-Clock Interchange
In an EPN with duplicated Tone-Clock circuit p acks, one circuit p ack is always

preferred

over the other. For the first Port Network in a cabinet, this is the
Tone-Clock circuit pack in carrier A. If a second Port Network is config ured in a
cabinet, its preferred Tone-Clock is the one in carrier E. The intention is that the
preferred circuit p ack be active whenever it is healthy. Once a failing preferred
Tone-Clock circuit pack has been replaced or repaired, the system will make it
active as soon as possible.
Control over interchanges for an EPN is accomp lished in essentially the same
ways as items 1 and 3 in the PPN case above. In ad dition, when the
non-preferred Tone-Clock circuit pac k in an EPN is active, and the preferred
circuit pack is repaired and proven c apable of filling its roles, the system will
automatically interchange back to it as soon as possib le.
Software Maintenance Interchange
Interchanges may be instig ated by software Tone-Clock maintenance in two
ways.
1. A scheduled Tone-Clock circ uit pack interchange oc curs accordi ng to the
parameters set by the change system-parameters maintenance
command. This can be d isabled or set to run weekly, but the stand ard
(default) situation is for it to occu r daily, at the time specified in the
system-parameters list for sched uled maintenance to beg in. This
interchange will be b locked if the lock switc hes are set, if the
non-preferred Tone-Clock circuit pac k in an EPN has been selected with
the set tone-clock command, if the stand by Tone-Clock has been set to
the busyout state, or if the cloc k generation capabili ty of the standby
Tone-Clock circuit pack is known to b e impaired. When this scheduled
interchange occ urs, the standby Tone-Clock circuit pac k becomes active
for a period of 20 second s to test its ability to generate c lock signals, and
then is returned to standby mode.
2. Unscheduled interc hanges occur when on-b oard Tone-Clock circuit pack
maintenance, or ongoing swi tch maintenance tests of TONE-BD,
TONE-PT, or TDM-CLK uncover failures seriou s enough to raise any
MAJOR or MINOR alarm against the active Tone-Clock circuit p ack.
International Settings [G3r V2]
The TN780 Tone-Clock circuit pack uses three firmware config uration parameters
for international support [ G3r V2]. The following two are automatically set by t he
software load for the targeted c ountry:
■The circuit pack’s cou ntry-code (USA, ITALY, AUSTRALIA, etc.)
■The circuit pack’s com panding mode (mu-Law or A -Law)