Nortel DMS-100 Series Maintenance Manual page 34

1-18 Maintenance overview
The LCC also provides system clocks for the DCC, RMM, and LCM. When
each unit of the LCM is active, LCC-0 is frequency-locked to the associated
primary DS-1 link. The LCC-1 clock is locked to LCC-0. The two LCC
clocks derive timing from the host LTC.
The DS30A ports in the LCA are numbered 0–7. The functions of the
DS30A ports appear in the following table.
LCA port assignments and use
Number
0,1, 2
3, 4, 5
6
7
DS-1 interface cards
The DS-1 interface cards (NT6X50) are in slots 19 and 20 of the HIE shelf.
An additional card can be provisioned in slot 21 in place of the filler panel.
Each DS-1 interface card accepts two DS-1 links from the host office
LGC/LTC. Each DS-1 interface card also connects the links on a maximum
of six links to the LCC.
297–8351–550 Standard 04.01 August 1999
Port type Functions
Primary Carries three message channels for the LCA shelf.
The system maps message channels to channels
1, 2, and 3 of each of the two primary DS-1 links to
the host office. The system maps channels that
carry speech to channels 4 through 24 of the
primary DS-1 links.
Image These ports are normally inactive. These ports
become active if the mate LCA and LCC are
inactive and takeover occurs. Port 3 takes over
mate port 0. Port 4 takes over mate port 1. Port 5
takes over mate port 2 of the mate LCA. The
system continues to map each channel to the
DS-1 links. The active LCC takes control of the
DS-1 links.
Interlink Provides a DS30A link for intershelf connections.
During call processing, the channels on this port
allow a subscriber line on one LCA to connect to a
subscriber line in the mate LCA. This action
leaves DS-1 channels to the host office free.
Maintenance Provides the LCA access to the RMM through the
LCCs. Through the RMM ports, separate line
circuits can be selected and metallic test access
(MTA) can connect to the tip and ring leads for
testing.