Esa Hardware - Nortel DMS-100 Series Maintenance Manual

3-4 ESA maintenance overview
The ESA processor is the only processor at the OPAC that can communicate
with the CM during ESA exit. The DMS-100 switch instructs the ESA
processor to exit ESA.
During ESA mode, call processing occurs through the ESA processor. The
ESA processor has a module of software, called the ESA CC.
The ESA CC emulates the DMS-100 switch CM and handles line-to-line
call processing. The ESA CC contains a subset of the translations data
found in the CM.
This subset is a snapshot of the CM data needed for ESA call processing.
The translation data in the snapshot data are static data. The system does not
enter the OPAC ESA mode until the ESA processor is loaded with static
data.
The download of the static data to the ESA CC0 from the CM truncates
some translations data. This condition means the static data are not subsets
of the CM and the system only supports basic calls.
During OPAC ESA mode, the system supports plain old telephone service
(POTS) and Meridian Digital Centrex (MDC) subscriber lines.
The ESA processor has a nailed-up direct communication link with the DMS
CC when the OPAC is not in ESA operation. The link is not available
during ESA operation. The ESA processor establishes the nailed-up
connection with the DMS CC after the links are restored. The DMS CC
must instruct the ESA processor to exit ESA. The ESA processor is the only
processor at the OPAC that can communicate with the DMS CC during ESA
exit.

ESA hardware

Feature package NTX154AA for the RLCM equipment frame has two
possible configurations.
1. The NT6X45AF based ESA package consists of three pieces of
equipment:
297-8211-550 Standard 05.01 August 1999
one ESA memory card (NT6X47AC), slot 14
one ESA processor card (NT6X45AF), slot 15
one ESA clock and tone card (NT6X75AA), slot 16