Figure 7-23.--Alarm contact maker arrangement.

systems aboard surface ships are capable of

Loudspeakers are usually provided with

generating and broadcasting collision alarms,

volume adjustments. The desired output level for

chemical attack alarms, and general alarms.

each loudspeaker will depend on where it is located.

Visual Alarm Indicators

Alarm Contact Makers

In areas where the noise level is high, such as

Alarm contact makers are installed at various

in engineering spaces and on hangar decks, visual

locations, such as the pilothouse/bridge and

alarm indicators are installed to alert personnel when

quarterdecks, where they are easily accessible to

an alarm is being sounded. The visual alarm

watch standers. The alarm contact makers are self-

indicators consist of lighting fixtures with red lamps

locking (in the OFF position), manual-release, lever-

installed in them. The red lamp lights steady when

operated switches. Operation of any alarm contact

the collision or chemical attack alarm is sounded and

maker will light both busy lights on all microphone

flashes when the general alarm is sounded.

control stations and transmit the alarm signal to all

1MC loudspeaker groups. Figure 7-23 is an

illustration of a typical alarm contact maker

OPERATIONAL SYSTEM TESTING

arrangement. The alarm contact makers are color

coded and prioritized according to their importance.

There are two methods for testing the system

The order of priority is controlled automatically by

for proper operation: (1) silent testing and (2) remote

relays in the control rack. The alarm contact makers

testing.

are color coded and prioritized as follows:

Silent Testing

1. Collision (green)

Since the system can operate on either

2. Chemical attack (yellow)

channel A or B and oscillator group 1 or 2, one

channel and one oscillator group can be on the line

3. General (red)

for ship's use while the other channel and group are

available for silent testing.

4. Unassigned A (gray)

To test channel A and oscillator group 1,

5. Flight deck crash (red)

proceed as follows:

If a low-priority alarm is being sounded and the

1. Place the LOAD DISC switch in the OFF

contact maker for a higher priority alarm is operated,

position.

the lower priority alarm will be silenced and the higher

priority alarm will be transmitted over the 1 MC

2. Place the AMPLIFIER CHANNEL

loudspeakers. Conversely, the operation of a low-priority

SELECTOR switch to the 1MC-B/6MC-B

alarm contact maker has no effect on a high-priority

position, and turn the OSCILLATOR

alarm that is being transmitted.

GROUP SELECTOR switch to the NO. 2

position. This puts channel B and

The nature and number of 1MC alarms

oscillator group 2 on the line, and leaves

installed aboard ship is dependent on the type and

channel A and oscillator group 1 available

mission of the ship. As a rule, however, all 1MC

for testing.

7.344

Figure 7-23.--Alarm contact maker arrangement.

7-19