Manual
Model 371A User Guide Issue 2, August 2019
Studio Technologies, Inc. Page 15
MODEL 371A
INTERCOM BELTPACK
Normal talk audio signals will not be con-
fused with a call signal. Digital filters within
the Model 371A’s processor integrated
circuit limits the microphone input’s high
frequency response to about 10 kHz. This
helps to ensure that false call detection
won’t take place. Digital filtering is also
performed on the audio input (Dante re-
ceiver) signals before they are sent to the
headphone output. This prevents users
with extended high-frequency sensitivity,
such as hosts and guests associated with
dog shows, from receiving undesirable
audio content.
To send a call signal is simple: just en-
able either or both of the talk buttons and
simultaneously press and hold the call
button. When call sending is active the or-
ange LED associated with the call button
will light. At the same time the channel or
channels that are active in their talk mode
will have their associated orange LED
flash. Release the talk button and/or the
call button and the sending of a call signal
will cease. As expected, pressing the call
button when neither talk channel is active
will result in nothing occurring.
Whenever a Model 371A audio input chan-
nel receives a call signal (20 kHz audio
tone) the orange LED on its companion
talk button will first flash and then light
continually. If a call signal is present on
both audio input channels then the orange
LEDs on both talk buttons will first flash
then remain lit. When receiving a call sig-
nal on either or both audio input channels
the orange LED associated with the call
button will not light.
By using a 20 kHz tone for call signaling
the Model 371A is compatible with legacy
intercom equipment, including the vener-
able RTS BP-325. When interconnecting
Model 371A and BP-325 units using an
appropriate Dante-enabled interface, such
as the Studio Technologies’ Model 45DR
Intercom Interface, call signaling is fully
compatible. Compatibility with the Clear-
Com method of call functionality is also
possible by using the Model 45DC Inter-
com Interface. (It converts the DC call sig-
nal 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 Interface will send and
receive 20 kHz signals that are be com-
patible with the Model 371A. 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. Audio signals received by the
Model 44D will be monitored for the pres-
ence of 20 kHz call signals. If call signals
are detected the GPO (general-purpose
output) signals will activate.
How to Identify a Specific
Model 371A
The Dante Controller software applica-
tion offers an Identify command that can
be used to help locate a specific Model
371A. When Identify is selected it will send
a command to a single Model 371A unit.
On that specific unit the three pushbutton
LEDs (talk 1, talk 2, and call) will light in a
unique pattern. In addition, the SYS and
SYNC status LEDs, located directly below
the etherCON RJ45 receptacle on the bot-
tom panel, will slowly flash green. After a
few seconds the LED identification pattern
will cease and normal Model 371A button
LED and Dante status LED operation will
resume.