Figure 9-19.--Individual alarm display module.

BATTERY CHARGER.-- The battery charger

conditions. However, it does not supply emergency

provides a floating charge to maintain the battery

power to operate the switchboard. The battery also

during normal switchboard operation. When the

supplies power to operate the alarm silence indicator

battery is charging, the battery voltage should be

when the visual-audible switch is in the VISUAL

position.

between 12 and 13.8 volts.

COMMON BOARD.-- The common board

contains the relays and circuitry to actuate all alarms.

It also contains the circuitry for ground detection,

dimming, and flashing lamp power.

POWER SUPPLY.-- There is a power supply

for each lo-line display alarm module. Each power

supply consists of a transformer and a bridge rectifier.

The output voltage of each power supply is approx-

imately 6.3 volts.

Line Display Section

The lower section of the switchboard is called the

line display section. This section contains all the

individual line display alarm modules. Figure 9-19 is

an illustration of an individual alarm display module.

Recognition of the state of the remote sensor

is accomplished by the alarm module (fig. 9-19). One

module is associated with each line circuit. Fig-

ure 9-20 illustrates an alarm module connected to a

Figure 9-19.--Individual alarm display module.

sensor circuit. A sensor circuit will be in one of three

Figure 9-20.--Alarm module type IC/M, functional diagram.