Nortel DMS-100 Series Maintenance Manual page 22

1-6 Maintenance overview
The XLCM contains 256 kB of RAM storage. The XLCM collects dial
pulse digits from subscriber lines and handles messages to and from the host
LTC or LGC. This action occurs for a maximum of 640 lines. The
NT6X51AB/AC requires XLCM software loads.
Before BCS28, LCMs had the NT6X51AA LCM processor card with 64 kB
of RAM storage capacity. The NT6X51AA requires LCM software loads.
The LCA shelf with these cards is NT6X04AA.
Digroup control card
The DCC (NT6X52) is in slot 05 of the LCA shelf. The DCC allows the
LCA and HIE shelves to communicate. The DCC provides an interface
between the corresponding LCM processor in the LCA and one link control
card (LCC). The LCC is in the HIE by way of eight DS30A links. The
following figure displays the actions of the DCC.
The DCC provides time switching to associate a line card to a given channel
on a DS30A link. The DCC also provides digital loop-around paths for fault
isolation.
RLCM DS30A to DS-1 interface
297–8351–550 Standard 04.01 August 1999
HIE shelf
LCC-1
(NT6X73)
To DS-1
interface cards
(NT6X50)
LCC-0
(NT6X73)
LCA shelf 1
DCC-1
(NT6X52)
8 DS30A
DCC-0
(NT6X52)
8 DS30A
LCA shelf 0
LCMP-1
(NT6X51)
To line drawers
(NT6X05)
LCMP-0
(NT6X51)