External Alarms Panels; Alarms; Office Alarm Unit (Oau) - Nortel DMS-100 Series Reference Manual

3-6 Office Alarm System Version 2
Table 3-1
Alarm control and display functions
Designation
Data Loop B
Data Loop A + B

External alarms panels

For information on external alarms panels, see Chapter 4.

Alarms

Office alarm unit (OAU)

In the Version 2 OAS, the primary alarm circuits are in the OAU dead
system with unique audibles (NT3X82) card. This card is on OAU and
standby MTM or ISM shelves. Two scan points on the NT3X82 cards,
ABOAUFL and ABMTMFL, monitor each other to provide a route to CC to
identify OAS system failures. The ABOAUFL scan point in the OAU shelf
monitors the NT3X82 card in the standby MTM or ISM. The ABMTMFL
scan point in the standby MTM or ISM monitors the NT3X82 card in the
OAU shelf. The OAS generates an ABOAUFL or ABMTMFL alarm at the
MAP terminal if the OAU or standby MTM shelf loses any of the following:
In some small offices, only the OAU contains the NT3X82 card. In these
offices, if the NT3X82 detects any of the alarm conditions listed above, the
alarm system generates the dead system alarm because there is no backup
NT3X82.
Version 2 dead system and OAU alarms
The scan and signal distribution points that generate the dead system and
OAU alarms are in NT2X82 cards in the OAU and standby MTM or ISM.
This configuration removes the requirement for separate scan and signal
297–1001–122 Standard 06.01 August 1999
(continued)
Device
Switch
(three-position)
Switch (locking)
–48V battery supply
130V dc supply for the remote alarm transfer circuit (if active)
130V ac, 20-Hz ringing supply for audible alarms
communication with the message switch (MS)
Function
Routes B aisle multiple to IOC port B, or MDF
data loop jacks, or opens the loop. For more
information, refer to Chapter 6.
Joins A and B aisle multiples. The IOC port B is
disconnected in this configuration. For more
information, refer to Chapter 6.
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