Instruction manual

3
BEARS 1
Audio Control System
1. DESCRIPTION The audio control system (ACS) was designed to meet the requirements of
the Brevard Emergency Amateur Radio Services, Inc. for the BEARS 1 vehicle. The system
allows all receiver and transceiver audio at a communications operating position to be monitored
through a single speaker or a headset. Seven audio inputs are provided and any combination
may be monitored. Each input has it’s own independent volume control. A sidetone monitor
with adjustable level control is available when using a headset. The ACS allows selection of one
of two microphones. A headset or desk microphone may be used and is selectable via a front
panel switch. Whichever microphone is being used along with push-to-talk (PTT) is switched to
the desired transceiver via the front panel selector. PTT may be accomplished using a foot
switch, hand switch or an integral microphone switch.
When the audio control panel is used at the Supervisor position, the composite outputs
(receive/transmit audio) from the other operating positions is input to the panel instead of the
individual radios. This allows the Supervisor to monitor the activities of the individual operation
positions. In addition to monitoring of the operating positions, three other radios/transceivers
including TV may be monitored.
An Intercom System (ICS) is included for communications between all operating positions and a
remote location (AUX) via the vehicles patch panel. The ICS is available only when using
headsets. Any position may signal any other position(s) using the call buttons. A blinking LED
and audible tone through the headset alerts the operator that he/she is being called. When in ICS
mode, the transmit audio and PTT is disabled. Receive audio, however, is still available in
addition to intercom audio in the headset. The microphone audio may also be routed to an
external PA system using the PA switch.
The Slideout J-Box located under Operating Position #1 includes ICS circuitry to combine and
route intercom signals to the various operating positions.
The Audio Control Panel has a dual digital clock for displaying local and UTC time
simultaneously. The clocks at all operating positions are synchronized to common time base.
The Audio Control Panel is housed in a 3.5 by 19 inch rack panel that is 5.5 inches deep. All
interface connections are via the rear panel. A remote headset / PTT J-box is mounted under
each operating position desk to keep cabling off the work area. Adaptation to the individual
radios of various models and manufacturers is accomplished using a custom interface cables.