Datasheet

Studio Technologies, Inc. Model 373A Intercom Beltpack, Issue 1, Page 2
The STcontroller software application is used to select the unit’s
operating parameters. The talk pushbutton switch can be config
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ured for optimal operation. Two “push-in/push-out” (“pop-out”)
rotary controls make it easy to set and maintain the desired
headphone output level. The Model 373A’s compact enclosure
is made from an aluminum alloy which offers both light weight
and ruggedness. A stainless steel belt clip, located on the back
of the unit, allows direct attachment to a user’s clothing.
The audio quality of the Model 373A is excellent, with low
distortion, low noise, and high headroom. Careful circuit design
and rugged components ensure long, reliable operation. A wide
range of applications can be supported, including education
and commercial theater, sports and entertainment TV and radio
events, streaming broadcasts, corporate and government AV,
post-production, and aerospace.
Dante Audio-over-Ethernet
Audio data is sent to and received from the Model 373A using
the Dante audio-over-Ethernet media networking technology.
As a Dante-compliant device, the Model 373A’s one audio
output (Dante transmitter) channel and two audio input (Dante
receiver) channels can be interconnected (routed) with other
devices using the Dante Controller software application. The
Dante transmitter and receiver channels are limited to support
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ing four Dante flows, two in each direction. The digital audio’s
bit depth is up to 24 with a sampling rate of 48 kHz. The Model
373A is AES67 compatible and compliant with the Dante Domain
Manager™ software application.
Two bi-color LEDs provide status indications of the Dante inter
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face. The Dante Identify command takes on a unique role with
the Model 373A. Not only will it cause the talk pushbutton’s
orange LED to light in a highly visible sequence, it will also turn
off (“kill”) the talk function if it is active.
Audio Quality
The Model 373A offers “pro” audio performance that is not
found in typical party-line (PL) intercom beltpacks. A low-noise,
wide dynamic-range microphone preamplifier and associated
voltage-controlled-amplifier (VCA) dynamics controller (com
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pressor) ensures that microphone audio quality is preserved
while minimizing the chance of signal overload. DC power to
support electret microphones can be enabled as required. The
output of the microphone preamp and compressor is routed to
an analog-to-digital converter (ADC) section that supports a
sampling rate of 48 kHz with a bit depth of up to 24. The audio
signal, now in the digital domain, travels through the processor
and on to the Dante interface section where it is packetized and
prepared for transport over Ethernet.
Audio input signals arrive via two Dante receiver channels. The
supported sampling rate is 48 kHz with a bit depth of up to 24.
The audio signals pass into the Model 373A’s processor where
channel routing, headphone level control, and sidetone creation
are performed within the digital domain. This provides flexibility,
allowing precise control of the audio signals and eliminating the
need for the two rotary level controls from having to directly
handle analog audio signals. The audio signals destined for the
2-channel headphone output are sent to a high-performance
digital-to-analog converter and then on to robust driver circuitry.
High signal levels can be provided to a variety of headsets.
Call Function Receive
A call receive function allows Model 373A users to be provided
with a visual indication that a call signal is active. The orange
LED within the pushbutton switch
will first flash then light
solid whenever a call signal is detected on either of the Dante
receiver (input) channels. Using 20 kHz tones, the call signals
are sent within the Dante audio channels (“in band”) allowing
interoperability between multiple Studio Technologies’ beltpack
units as well as being compatible with legacy party-line intercom
systems. Call signals can be useful to indicate to users that they
are needed “on headset” or should be actively listening to an
intercom channel. The call function can also be used to provide
real-time cues to production personnel during the running of
live events.
Configuration Flexibility
A highlight of the Model 373A is its ability to be easily config-
ured to meet the needs of specific users and applications. All
configuration choices are made using the STcontroller software
application that communicates with the Model 373A by way of an
Ethernet network connection. Configurable parameters include
microphone power and preamplifier gain, headphone monitoring,
sidetone audio operation, and talk button operation.
The microphone input can be selected for compatibility with
dynamic or electret (DC-powered) microphones. The gain of
the microphone preamplifier can be selected from among five
choices. These choices allow compatibility with the variety of
microphones that are part of broadcast, intercom, and computer
gaming headsets.
To support optimum user performance, the Model 373A’s talk
pushbutton switch can be configured from among three choices:
Push to Talk, Latching, or Push to Talk/Tap to Latch. Two audio
channels arrive via Dante receivers (inputs) and are destined
for the 2-channel headphone output. Each input source can
be independently routed to the left headphone channel, right
headphone channel, or both the left and right headphone chan
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nels. This flexibility allows a variety of listening environments
to be created, including stereo, single-channel monaural, and
dual-channel monaural.
Note that the left headphone output is sent to both the 4-pin
male XLR connector (Headset A) and the 3.5 mm 4-conductor
TRRS jack (Headset B). However, the right headphone output