User Guide

Model 373A User Guide Issue 1, April 2019
Studio Technologies, Inc. Page 15
MODEL 373A
INTERCOM BELTPACK
An exception is if both Dante input channels
are routed to only the left headphone output
channel. In this case sidetone audio will only
be sent to the left headphone output channel.
The exact sidetone level is configured from
among five values within the STcontroller
application. There is also a selection choice
for turning off sidetone. There is no means
of adjusting the sidetone level using a physi-
cal button or control on the Model 373A unit.
Also, the two headphone level controls on the
top panel of the unit do not impact the side-
tone level.
In most cases the exact sidetone level set-
ting is not critical and typically users will not
be concerned about revising it. But setting
the sidetone level to something reasonable is
important. Setting the level too low will en-
courage users to speak too loudly; setting it
too high and users will be tempted to speak
hesitantly. And while users aren’t provided
with a sidetone level control or other adjust-
ment means, should the need arise STcon-
troller allows rapid adjustment of the sidetone
level. In most cases the default sidetone level,
Medium, should provide an appropriate level.
Call Detection Display
A Model 373A function allows a call signal
that’s present on either Dante receiver (input)
channel to cause the pushbutton switch’s
LED to light. Whenever a call signal is detect-
ed the talk button’s orange LED will first flash
and then light continually. Technically, a call
signal is achieved by sending a 20 kHz audio
tone on the desired Dante audio channel.
This signal is summed (mixed) with normal
talk audio. The Model 373A’s two audio input
channels continually monitor the audio input
for the presence of 20 kHz.
The detection circuitry will not confuse normal
talk audio signals with a call signal. Digital
filters within the Model 373As processor help
to ensure that false call detection won’t take
place. Digital filtering is also performed on
the microphone audio output signals as well
as the audio input (Dante receiver) signals
before they are sent to the headphone
outputs. This prevents users with extended
high-frequency sensitivity, such as hosts
and guests associated with dog shows, from
receiving undesirable audio content.
By using a 20 kHz tone for call signaling
the Model 373A is compatible with legacy
intercom equipment, including the venerable
RTS BP-325 beltpack. When interconnect-
ing Model 373A and BP-325 units using an
appropriate Dante-enabled interface, such
as the Studio Technologies’ Model 45DR In-
tercom Interface, call signaling is fully com-
patible. Compatibility with the Clear-Com®
method of call functionality is also possible
by using the Model 45DC Intercom Interface.
(It converts the DC call signal associated
with pin 3 of a Clear-Com party-line circuit
to a 20 kHz tone.) Also, devices such as the
Studio Technologies’ Model 44D Audio In-
terface will send and receive 20 kHz signals
that are be compatible with the Model 373A.
The Model 44D converts its GPI (general-
purpose input) signals to 20 kHz tones and
sums them with the audio signals which are
then transported “in band” via the Dante
audio paths.
How to Identify a Specific
Model 373A
Both the Dante Controller and STcontroller
software applications offer a command that
can be used to help locate a specific Model
373A. When the Identify command is select-
ed it will send a message to a single Model
373A unit. On that specific unit the pushbut-
ton switch’s orange LED will flash rapidly. In
addition, the SYS and SYNC status LEDs,
located directly below the etherCON RJ45