126 Installing the Alarm System
Practice 450-1011-201
Figure 15-2
Front Panel of an LIU Equipped with an ALIU
::::::::::::::::::::
::::::::::::::::::::
:::::::::::::::::::::::::::::::
Power
Light
TELADAPT
Jack from
LANlink
Line
RS-232-C Connectors
Parallel Port
LAN Interface Unit
(ALIU Equipped)
:::::::::::::::::::::::::::::::
::::::::::::::::::::
RS-232 -C Port for
Connecting to the
LIU Port Assigned to
the Alarm System
DB37 Connector for
Customer Alarms
LP TST
ACO
450-0033
::::::::::::::::::::
Connector to the Frame
Supervisory Panel of Bay
Systems (reserved for future
use with cabinet systems)
CR
LNK OK
MJ
MN
P2
P3
P4
Table 15-A
Pin Assignments for the Customer Interface Connector (P4)
Note 1: Each pair of pins (that is, each relay closure circuit) is independent and isolated from all other
pairs. The pairs are denoted by the same name, prefixed by a + or a -.
Note 2: To generate an alarm on an input line (ALARM ACTIVE), the plus and minus pins of the pair
for that line require the following input signals:
•
On each + pin, provide a BR (battery return) signal.
•
On each - pin, provide a -48 V input.
To remove an alarm from an input line, that is, no alarm is present (ALARM INACTIVE), the plus
and minus pins of the pair for that line require the following input signals:
•
On each + pin, provide a -48 V input or no contact (-48 V is recommended to avoid a ‘floating
pin’ condition).
•
On each - pin, provide a -48 V input.
Note 3: The output lines (CRA, CRV, MJA, MJV, MNA, MNV, BAY, AUXREL1, and AUXREL2) are
relays in the ALIU that operate by opening and closing as follows:
•
An ACTIVE ALARM is signified by closure of the relay between the + and - pins. Maximum
current through the relay is 0.4 A (relay closed).
