TM 11-5805-424-15/NAVSHIPS 0967-220-9013/TO 31W2-2G-41
module. Therefore, the receive loss of carrier alarm
made to disable all alarm circuitry, by setting ALARM
circuits and the no-transition receive alarm circuits.
switch 1A1S6 to DISABLE.
respectively, are deactivated.
b. No-Transition Send Alarm. The no-transition
(4) When activated, window timer QS, Q6, Q7
times out an additional 0.75 second of delay (adjustable
send alarm is activated if no data transitions are in the
by TALK REQUEST WINDOW resistor 1A1R 101,
send circuits for 5 seconds or longer.
resulting in a total delay (from the two timers
approximately 1.75 seconds, slightly longer than the
(1) Input data from amplifier DIA-1 is applied to
talk-request signal. After the delay, window timer Q5,
AND gates GAS-1 and GAS-2. The two gates, working
Q6, Q7 provides a positive output (ground) that is
in conjunction, pass both the positive signal transitions
inverted to a negative signal by amplifier IN-17 for
and the inverted negative signal transitions (as positive
application to NAND gate GAD-3. This high from the
transitions) to delay driver Q5, Q6, Q7. As long as
window timer for an additional 75 seconds, insures that
positive pulses are applied (time between transitions is
NAND GATE GAD-3 is enabled to clear FFB-1 through
not greater than 200 milliseconds), delay driver Q5, Q6,
IN-18 when the 1.5 seconds TALK-REQUEST signal is
Q7 remains inactive, providing a negative input that
removed when a valid TALK-REQUEST is relieved.
maintains 5second delay Q8 deactivated. The resultant
positive output from 5-second delay Q8 is inverted to a
(5) After order-wire circuit operation is concluded,
negative level by amplifier IN-3 and applied to OR gate
operation of the TALK REQUEST RESET pushbutton
GOB-1. With no other alarm condition present, OR gate
provides + 15 volts to bistable FFB-1 The resultant
GOB-1 is inhibited e below), providing a low-level output
positive output at bistable FFB-1 output 1 is inverted to
that is inverted by amplifier IN-5. The resulting high-
a negative signal by amplifier IN-19, extinguishing the
level (+15 volts) output from amplifier IN-5 holds
TALK REQUEST indicator lamp.
ALARM indicator lamp 1A1DS2 in the off condition.
(6) If a true alarm condition exists at the input to
(2) If data transitions occur at intervals greater
amplifier IN-10, AND gate GAD-3 is held inhibited,
than 200 milliseconds but less than 5 seconds apart,
providing a positive input to amplifier IN-18. This action
delay driver Q5, Q6, Q7 provides a positive input to
prevents any reaction by bistable FFB-1 which is
activate 5-second delay Q8. The next transition resets
therefore held in a condition that prevents TALK
delay driver Q5, Q6, Q7 and 5-second delay Q8.
REQUEST indicator lamp DS3 from being lighted during
an alarm condition (which must last for more than 2
(3) If no transition is received after 5 seconds, 5-
seconds).
second delay Q8 times out, providing a low-level input
to amplifier IN-3. The resultant high-level output from
5-24. Alarm Circuits (fig. 8-5)
amplifier IN-3 enables OR gate GOB-I and provides a
high-level output which, inverted by amplifier IN-5
a. General. Four alarm circuits sense loss-of signal
provides ground to light ALARM indicator lamp 1A1DS2.
The +6 volts from amplifier IN-3 allows amplifier IN-4 to
transitions and loss-of-carrier signals. A common alarm
conduct and apply a ground level to the NO
circuit and an ALARM indicator lamp are activated when
TRANSITION ALARM SEND output terminal, to activate
any of the four alarm conditions exists. External
an external no-transition send alarm.
terminal connections are provided for connecting
individual alarms that will light according to the actual
(4) The no-transition send alarm may be
single alarm condition that exists when the common
deactivated by applying a high-level input (+6 volts)
ALARM indicator lamp is lighted. A no-transition alarm
through OR gate GOA-1; this action applies a steady
will be activated if signal transitions do not occur for a 5-
positive level to delay driver Q5, Q6, Q7, keeping 5-
second period. A carrier alarm will be activated if the
second delay Q8 deactivated ((1) above). The positive
carrier is interrupted longer than 2 seconds. Provisions
input to GOA-1 may be
are
Change 5
5-26
