Nortel DMS-100 Series Maintenance Manual page 197

use the test (TST) command with the REX option. These tests require that
both LCM units of the OPM, RMM and ESA processor are InSv.
The REX test tests the ability of the LCM units to enter and exit ESA mode.
The REX also tests the ability of the LCM units to send messages to the ESA
processor while in ESA mode. The system tests one LCM unit at a time. If
the system tests both units at the same time, a loss of service results. The loss
of services affects calls connected at the time of the test. While the system
tests one unit, the other unit continues call processing in the takeover mode.
The system prevents accidental attempts to perform maintenance on an LCM
unit that is in ESA mode. The system runs a lockout task on the tested LCM
unit. The lockout task is the same task that the system uses during an ESA exit.
Lockout does not perform any maintenance.
Takeover and take back on an LCM unit affects calls that the system
connected. This condition does not affect calls that the system already
connected. The system returns the LCM to service before the system tests the
other unit.
The following actions occur during a REX test:
1. The system tests the messaging ability of the peripherals, ESA module,
LCM units, and RMM. If any of these preliminary tests fail, the system
does not run REX tests.
2. If the preliminary tests pass, the system places one LCM unit in the ESA
mode and the other unit in the takeover mode. This action switches the
messaging links of the unit in the ESA mode from the host to the ESA
module.
3. The ESA processor tests the ability of the LCM units to message to the
ESA module under ESA conditions.
4. The system performs other diagnostics on the ESA module. These
diagnostics are the tones test and a comparison of LCC control and 6X75
status bytes.
5. After the tests are complete, the system takes the unit from the ESA mode
and returns the unit to service.
6. If the REX tests pass, the system tests the ESA module with the other
LCM unit.
ESA ROM diagnostics
The ESA processor has a ROM diagnostic test. Operating company personnel
can implement this test with the LOADPM command.
This test consists of the standard XPM ROM tests. These tests test the
processor and memory complex, and also basic messaging functions. The
DMS-100 Family OPM Maintenance Manual ISN07 (TDM)/SN07 (DMS) and up
ESA maintenance overview 4-29