Nortel DMS-100 Series Reference Manual page 18

1-4 Introduction
The alarm system uses scan (SC) points and SD points to monitor and report
the alarm status of each equipment row, to a maximum of 40 rows. Scan
points detect voltage, ground, open-loop, or closed-loop conditions. Signal
distribution points transfer alarm indications to alarm panels and other
equipment. Hardware switch settings and datafill in tables ALMSCGRP,
ALMSC, ALMSDGRP, and ALMSD define the scan and signal distribution
points.
Alarm and control inputs that the alarm system hardware monitors connect
to the alarm system software through scan (SC) points. These scan points
detect signal inputs generated by the following:
The descriptions of tables ALMSCGRP, ALMSC, ALMSDGRP, and
ALMSD in the data schema section of Tranlations Guide describe SC point
and SD point assignments for the OAS.
The software that monitors the SC points forms the external (EXT) alarms
subsystem of the DMS maintenance system. For more information, see
External Devices Maintenance Guide, 297-1001-593.
System alarm detection
Alarm and control inputs that the software in maintenance subsystems other
than EXT generates are called system inputs. Each maintenance subsystem
controls its alarm status display in the system status area of the Ext level
MAP display (shown in Figure 1-2). The alarm system software checks for
changes in the alarm status of the maintenance subsystems every five
seconds and updates audible and visual alarm indications when alarm status
changes occur.
297–1001–122 Standard 06.01 August 1999
hard-wired alarm contacts in DMS hardware
operation of manual-control switches
alarm circuits in miscellaneous DMS and non-DMS equipment in the
central office
analog trunk circuit-wired contacts