Nortel DMS-100 Series Maintenance Manual page 156

3-6 PRLCM overview
Table 3-1 LCA port assignments and use (Sheet 2 of 2)
Number
6
7
PCM30 interface cards
The PCM30 interface cards (NT6X50) are located in slots 19 and 20 of the HIE
shelf, and an additional card may be provisioned in slot 21 in place of the filler
panel. Each PCM30 interface card accepts two PCM30 links from the host
office LGC/LTC and connects them on up to six links to the LCC.
A minimum of two PCM30 cards are required so the two primary message
channels from the LCM are carried on different cards for reliability. A third
PCM30 card is added only if six PCM30 links to the host are needed to handle
the traffic load of the PRLCM.
PCM30 ports are not duplicated, but each processor in the LCA shelves of the
PRLCM can control all six PCM30 ports.
Primary ports that map one to one with PCM30 links are known as equipped
ports. The number of equipped ports in an LCA depends on the number of
PCM30 interface cards provisioned in the HIE. If three PCM30 cards are
provisioned, all three primary ports (0, 1, 2) for each LCA are equipped. If a
port is unequipped, its ports are either not used or are used for features
contained in additional PRLCM feature packages, if provisioned.
Note: Links 0 and 1 are message-supporting links that have special
maintenance protection applied to them. On each PCM30
message-supporting link, a channel 12 looparound connects the outgoing
side of channel 12 to the incoming side of channel 12. This looparound is
called extended PCM30 maintenance. The looparound prevents manually
busying the link where the looparound is applied when the unit it supports
is still in service. When the unit this link supports is manually busied, the
looparound (extended PCM30 maintenance) is disabled. At this time, the
link can be busied and the looparound is reenabled as NT6X50 card
diagnostics for maintenance of the PCM30 link.
297-8361-550 Standard 04.01 September 2000
Port type Functions
Interlink Provides a DS30A link for intershelf connections.
During call processing, the channels on this port
allow a subscriber line on one LCA to be connected
to a subscriber line in the mate LCA, leaving PCM30
channels to the host office free.
Maintenance Provides the LCA access to the RMM through the
LCCs. Through the RMM ports, individual line
circuits can be selected and metallic test access
(MTA) connections can be made to the tip and ring
leads for testing.