TM 5-6350-264-14&P-8
NAVELEX EE181-AA-OMI-090/E121 SA-1954
T.O. 31S9-2FSS9-1-8
Table 2-1. Operator Controls and Indicators
Controls and
Function
indicators
Alarm switch
Provides an alarm signal output when actuated.
NOTE
After an alarm has been responded
to, notify appropriate direct sup-
port maintenance personnel to
reset the LAS to a no-alarm
condition.
Alarm indicator
LED comes on when alarm is actuated;
goes off when alarm switch is reset.
Section II. THEORY OF OPERATION
2-3. FUNCTIONAL DESCRIPTION.
age is applied to one side of the latching relay. With the
latching relay operating and latched, the closed latching
a. The LAS permits authorized personnel to manually
relay contacts provide a continuous signal path and
activate an alarm signal to the J-SIIDS Control Unit
return path through an LED. The indicator light (LED),
when the security of an area is threatened. The LAS
on the front of the LAS comes on red and remains on as
chassis cover contains a tamper switch that also
long as the duress alarm signal is present. The indicator
activates an alarm signal when the cover is
light goes out when the reset switch is pressed and the
removed from the housing by inch (0.635 cm) or
LAS returns to the no-alarm state.
more. See figure 2-2 for a simplified functional
block diagram of the LAS.
(2) Duress alarm reset. When the duress alarm
switch is actuated, the alarm signal and the alarm
indicator light will remain on until the reset switch is
b. The LAS has four operational modes as follows:
pressed. When the reset switch is pressed, voltage is
duress alarm, duress alarm reset, tam-per alarm,
applied to the other side of the latching relay which
and no alarm.
restores the relay contacts to the no-alarm condition.
(1) Duress alarm. When an operator actuates the
(3) Tamper alarm. When the cover is moved from
duress alarm switch, the low impedance across TB1-1
the chassis by 1/4 inch (0.635 cm) or more, a tamper
and TB1-2 is changed to a high impedance which is
alarm switch on the inside of the cover activates a
used as the duress alarm signal output. When the
tamper alarm signal. When the cover
duress alarm switch contacts open, volt-
2-2
