Federal Signal 640000 Siren, 640 Series, 100 W, programmable slide switch and light control

The Federal Signal Model PA640 (figure 1-1) is a
precision built, efficient and economical full-featured
electronic siren and light control system. The siren
provides wail, yelp, and priority or high-low siren
tones as well as the horn ring transfer Tap II feature,
public address (PA), radio rebroadcast and an air
horn sound.

On-board relays in the unit allow centralized
control and wiring of primary, secondary, alley lights,
and auxiliary circuits with a lighted rubberized
membrane switch assembly. A convenient four-
position Mode slide switch allows simplified and
rapid selection of most common siren and lighting
functions and changes the horn ring function accord-
ingly to provide the Tap II feature.

The unit may be installed in negative ground
vehicles with 12-volt electrical systems. The siren
circuits are protected against failure by user-supplied
fuses. The audio power amplifier contains circuitry
that protects the output transistor stages against
speaker and wiring short circuits. The relay outputs
are protected against failure by user-supplied fuses.
No components protrude from the bottom of the siren
to interfere with mounting arrangements.

A noise-canceling microphone is provided. It
provides high quality voice reproduction without
feedback squeal. The microphone push-to-talk switch
overrides any siren sound for instant Public Address
use. PA volume is adjustable by means of a front
panel VOLUME control.

The PA640 is designed to drive one 11-ohm
impedance, high power (100W) speaker.

To be discontinued