User Guide

1.0 DESCRIPTION
1.1 The ACR/EM-1A, 1D is a battery operated solid state megaphone
specifically developed for use in enclosed areas such as in the interior of
an aircraft or ship cabin. It has been designed to minimize regenerative
acoustic feedback that results in whistling and other oscillations of this
nature. It has a 90° sound projection angle to direct the sound to persons
in its immediate vicinity, as well as in the rear sections of any aircraft.
The amplifier frequency band-pass has been selected to produce a crisp,
clear reproduction of voice signals. The operating power level is also
sufficient to provide adequate sound under high ambient noise level
conditions without being over-powering. Specific attention has been
given to the physical size so that it can be used effectively in a crowded
environment.
The EM-1A & EM-1D are the same except for installed options:
OPTIONS MATRIX
MODEL MANUAL GAIN ALARM ACTUATOR BATTERY MONITOR
Visual Audible
EM-1A Yes Yes Yes No
EM-1D Yes No Yes Yes
1.2 The integrated circuit amplifier only uses a small current when turned
“ON”. Large currents necessary to drive the speaker are utilized only on
voice peaks. This extends the life of the batteries so that several hours of
operation may be expected when used normally in an intermittent manner.
Batteries should be replaced periodically as recommended by the
manufacturer. (See section 5.0) A simplified block diagram of the
megaphone is shown in Figure 1.
2.0 TECHNICAL DATA
Dimensions 5.5” max diameter bell, 11.5” max long
Weight 2.3 lbs., including batteries
Materials Horn, handle – Anodized Aluminum
Housing – Aluminum
Attachment Neck strap at top of unit
Y1-03-0014 Rev. R
2