Datasheet

Studio Technologies, Inc. Model 371A Intercom Beltpack, Issue 2, Page 2
technology. As a Dante-compliant device, the Model 371A’s
two audio output (Dante transmitter) 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 supporting 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 371A is AES67 com
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patible and compliant with the Dante Domain Manager™
software application.
Two bi-color LEDs provide an indication of the Dante con
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nection status. The Dante Controller’s
Identify command
takes on a unique role with the Model 371A. Not only will
it cause the talk and call button LEDs to light in a unique
highly visible sequence, it can also be configured to turn
off any active talk channels.
Audio Quality
The Model 371A’s completely “pro” performance is coun-
ter to the less-than-stellar reputation of typical party-line
(PL) intercom audio. A low-noise, wide dynamic-range
microphone preamplifier and associated voltage-con
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trolled-amplifier (VCA) dynamics controller (compressor)
ensures that microphone audio quality is preserved while
minimizing the chance of signal overload. DC power to
support electret microphones can be enabled if necessary.
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 371A’s pro
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cessor where channel routing, headphone level control, and
sidetone creation are performed within the digital domain.
Two push-in/push-out (“pop out”) rotary controls make it
easy to set and maintain the desired headphone output
level. The audio signal destined for the headphone output
is sent to a high-performance digital-to-analog converter
and then on to a robust driver circuit. A high signal level
can be provided to a variety of headsets, headphones,
and earpieces.
Call Function
A call function allows Model 371A users to send and
receive channel-specific visual alert signals. Pressing the
call pushbutton on the top of the unit is all that’s required
to signal other users that attention is requested. Using 20
kHz tones, the call signals are sent within the audio chan
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nels (“in band”) allowing interoperability between multiple
Model 371A units as well as being compatible with legacy
party-line intercom systems. The call function 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 371A is its ability to be easily
configured to meet the needs of specific users and ap
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plications. All configuration choices are made using the
STcontroller software application that communicates with
the Model 371A by way of an Ethernet network connec
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tion. Configurable parameters include microphone power
and preamplifier gain, sidetone audio operation, and talk
button operation.
The microphone input can be selected for compatibility
with dynamic or elected (DC-powered) microphones. The
gain of the microphone preamplifier can be selected from
among four choices. These allow compatibility with the
variety of microphones that are part of broadcast and
intercom headsets.
A unique Model 371A feature is the ability to individu
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ally configure the way in which the two talk pushbutton
switches function; four choices are available. For standard
intercom beltpack operation it’s typical to select
Push to
Talk
, Latching , or Push to Talk/Tap to Latch . For situations
where only monitoring of an intercom channel is desired a
Disabled mode is available.
Ethernet Data and PoE
The Model 371A connects to an Ethernet data network
using a standard 100 Mb/s twisted-pair Ethernet inter
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face. The physical interconnection is made by way of a