Datasheet

Studio Technologies, Inc. Model 374A Intercom Beltpack, Issue 3, Page 2
ensure long, reliable operation. A wide range of applica-
tions can be supported, including sports and entertainment
TV and radio events, streaming broadcasts, corporate
and government AV installations, and post-production
facilities.
Dante Audio-over-Ethernet
Audio data is sent to and received from the Model 374A
using the Dante audio-over-Ethernet media networking
technology. As a Dante-compliant device, the Model 374A’s
four audio output (Dante transmitter) and four 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 374A is AES67 com
-
patible and compliant with the Dante Domain Manager™
software application.
Two bi-color LEDs provide an indication of the Dante con
-
nection status. The Dante Controller’s
Identify command
takes on a unique role with the Model 374A. Not only will
it cause the talk 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 374A’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
-
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 four 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 374A’s
processor where channel routing, headphone level control,
and sidetone creation are performed within the digital
domain. This provides flexibility, allowing for precise control
of the audio signals and eliminates the need for the four
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,
headphones, and earpieces.
Call Function
A call function allows Model 374A users to receive and
send channel-specific visual alert signals. Using 20 kHz
tones, the call signals are sent within the audio channels
(“in band”) allowing interoperability between multiple
Model 374A 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 realtime cues to
production personnel during the running of live events. Call
signals present on the four audio input (Dante receiver)
channels can be detected and displayed. Pushbutton 4, on
the Model 374A’s top panel, can be configured to serve as
a call button. This allows a call signal to be generated for
talk channels 1, 2, and 3.
Configuration Flexibility
A highlight of the Model 374A is its ability to be easily
configured to meet the needs of specific users and ap
-
plications. All configuration choices are made using the
STcontroller software application that communicates with
the Model 374A by way of an Ethernet network connection.
Configurable parameters include microphone power and
preamplifier gain, sidetone audio operationl, talk button
operation, and headphone monitoring.
The microphone input can be selected for compatibility
with dynamic or electret (DC-powered) microphones.