User Guide
Model 373A User Guide Issue 1, April 2019
Studio Technologies, Inc. Page 7
MODEL 373A
INTERCOM BELTPACK
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 de-
tected on either of the Dante receiver (input)
channels. Using 20 kHz tones, the call sig-
nals 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 need-
ed “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 configured to meet the needs of
specific users and applications. All configura-
tion choices are made using the STcontroller
software application that communicates with
the Model 373A by way of an Ethernet net-
work 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 micro-
phones 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
channels. This flexibility allows a variety of
listening environments to be created, includ-
ing stereo, single-channel monaural, and
dual-channel monaural.
Note that the left headphone output is sent
to both the 4-pin male XLR connector (Head-
set A) and the 3.5 mm 4-conductor TRRS
jack (Headset B). However, the right head-
phone output channel only connects to the
3.5 mm 4-conductor TRRS jack (Headset B).
Ethernet Data and PoE
The Model 373A connects to an Ethernet
data network using a standard 100 Mb/s
twisted-pair Ethernet interface. The physical
interconnection is made by way of a
Neutrik® etherCON RJ45 receptacle.
While compatible with standard RJ45 plugs,
etherCON allows a ruggedized and locking
interconnection for harsh or high-reliability
environments. An LED displays the status
of the network connection.
The Model 373A’s operating power is pro-
vided by way of the Ethernet interface using
the 802.3af Power-over-Ethernet (PoE)