Studio Technologies 380 User manual

Copyright © 2017 by Studio Technologies, Inc., all rights reserved
www.studio-tech.com
50625-0217 Issue 2
User Guide
Issue 2, February 2017
This User Guide is applicable for serial numbers
M380-01001 and later with application firmware 2.1 and later
and Dante firmware 2.0 (Ultimo 3.10.1.12) and later
Model 380 On-Air Beltpack

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Model 380 User Guide Issue 2, February 2017
Studio Technologies, Inc. Page 3
Table of Contents
Revision History ............................................................ 4
Introduction ................................................................... 5
Getting Started .............................................................. 9
Operation ...................................................................... 15
Technical Notes ............................................................. 18
Specifications ................................................................ 22
Appendix A: Model 380 Block Diagram ....................... 23

Issue 2, February 2017 Model 380 User Guide
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Revision History
Issue 2, February 2017:
1. Documents change to 6-position DIP switch. Allows expanded headphone output
modes.
Issue 1, September 2016:
1. Initial release.

Model 380 User Guide Issue 2, February 2017
Studio Technologies, Inc. Page 5
Introduction
The Model 380 On-Air Beltpack offers a
unique combination of audio resources,
providing main and talkback outputs,
talent cue (IFB) input capabilities, and
essential user controls in a compact,
portable package. Optimized for broad-
cast sports and live entertainment events,
news-gathering, and streaming broadcast
applications, the unit allows incredibly
simple deployment while maintaining
“pro” audio quality and an intuitive user
experience. The Model 380 integrates di-
rectly into both Dante audio-over-Ethernet
and standard analog audio environments.
With just a Power-over-Ethernet (PoE)
connection, a dynamic microphone, and
a pair of headphones or an earpiece, a
complete broadcast “stand-up” on-air
position can be created. And by using the
Model 380’s microphone output a direct
connection to an analog microphone-level
input on an associated camera, camcord-
er, or audio console is also supported. Key
features can be easily configured includ-
ing microphone preamplifier gain, talk-
back button operation, headphone signal
routing, and sidetone operation.
The Model 380’s audio quality is excellent,
with low distortion, low noise, and high
headroom. Careful circuit design and
rugged components ensure long, reli-
able 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. By providing the main
(on-air) audio signal in two forms, Dante
digital audio and analog microphone
level, the Model 380 makes integration
into a wide range of environments easy to
accomplish. And with the talkback au-
dio available as a Dante output channel,
routing it to inputs on a variety of devices,
such as matrix intercom systems, audio
consoles, and monitor loudspeaker sys-
tems, is simple and flexible.
Applications
The Model 380 on its own can provide
an “all-Dante” solution for one on-air talent
location. Two Dante audio input channels
supply the user with their talent cue (IFB)
signals. Should the cue signal be “mix-
minus” an integrated sidetone function
can provide the user with a microphone
Figure 1. Model 380 On-Air Beltpack top and bottom views

Issue 2, February 2017 Model 380 User Guide
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confidence signal. Two Dante audio
output channels, one designated as main
(for on-air) and the other talkback, are
routed via an associated local-area net-
work (LAN) to inputs on Dante-compatible
devices. A pushbutton switch, located
on the Model 380’s top panel, provides a
combination talkback and “cough” (user-
controlled audio mute) function. When
talkback is not active audio from the out-
put of the unit’s microphone preamplifier
is routed to the Dante main output chan-
nel; the Dante talkback output channel
is muted. When the talkback function
is active audio is muted on the Dante
main output channel and activated on
the Dante talkback output channel. The
audio switching is performed in the digital
domain and is virtually “click-free.”
Other applications may benefit from not
utilizing the Model 380’s Dante main out-
put channel. This typically won’t be an
issue of inadequate audio quality but
rather a need to match work-flow require-
ments. For example, for lip-sync or trans-
mission purposes it may be optimal to
have the on-air audio transported as an
embedded signal along with the associ-
ated camera video. Alternately, all on-air
audio sources may need to connect to
inputs on an audio console or console-
related I/O unit. Supporting these sce-
narios is not a problem as the Model 380
supplies a microphone output connec-
tion that’s specifically intended for this
purpose. Simply connect the unit’s micro-
phone output connection to the desired
analog input, such as the mic/line input
on an ENG-style camera—that’s it!
The circuitry associated with the Model
380’s microphone output is very simple,
essentially a passive path that routes a
signal connected to the microphone input
connector directly to the microphone
output connector. A solid-state circuit,
in series with the mic in-to-mic out path,
allows muting of the signal on the micro-
phone output connector whenever the
talkback function is active. And it’s impor-
tant to note that using the microphone
output connection doesn’t impact the
normal functioning of the Dante main and
talkback output channels. This can be
valuable, such as when utilizing the Dante
main output channel as a back-up, sec-
ondary, or redundant on-air audio signal.
Setup and Operation
Set up and operation of the Model 380 is
simple. An etherCON® RJ45 jack is used
to interconnect with a standard twisted-
pair Ethernet port associated with a PoE-
enabled network switch. This connection
provides both power and bidirectional
digital audio. A handheld (“stick”) micro-
phone or broadcast stereo or monaural
headset with a dynamic microphone can
be directly connected to the unit’s 3-pin
XLR input connector. Stereo headphones,
the headphone connections from a stereo
or monaural headset, or even a monaural
earpiece are connected to the phones
output jack.
Three “push-in/push-out” rotary level
controls make it easy to set the level of
the talent cue (“IFB”) and sidetone levels
being sent to the 2-channel headphone
output. The Model 380’s enclosure is
made from an aluminum alloy which offers
both light weight and ruggedness. A stain-
less steel “belt clip,” located on the back
of the unit, allows direct attachment to a
user’s clothing.

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Dante Audio-over-Ethernet
Audio data is sent to and received from
the Model 380 using the Dante audio-over-
Ethernet media networking technology. As
a Dante-compliant device, the Model 380’s
two output (Dante transmitter) and two
input (Dante receiver) audio channels
can be assigned to other devices (routed)
using the Dante Controller software appli-
cation. 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 44.1 or 48 kHz. Two
bi-color LEDs provide an indication of
the Dante connection status.
Audio Quality
The Model 380’s performance is com-
pletely “pro” with capabilities not expected
in something of such diminutive propor-
tions. A low-noise, wide dynamic-range
microphone preamplifier and associated
voltage-controller-amplifier (VCA) dynamics
controller (compressor) ensures that mic
input audio quality is preserved while
minimizing the chance of signal overload.
The output of the microphone preamp
and compressor is routed to an analog-to-
digital conversion (ADC) section that sup-
ports sampling rates of 44.1 and 48 kHz
with a bit depth of up to 24. The audio
signal, now in the digital domain, routes
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 the Dante
receiver channels and pass into the Model
380’s processor. The sampling rate will be
44.1 or 48 kHz with a bit depth of up to 24.
Channel routing, headphone level control,
and sidetone creation are performed within
the digital domain. This provides flexibil-
ity, allows precise control, and keeps the
three level potentiometers (two for audio
inputs and one for sidetone) from having to
directly handle analog audio signals. The
two audio channels destined for the phones
outputs 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.
Configuration Flexibility
Several configuration choices are available,
allowing the Model 380 to meet the needs
of specific applications and user preferenc-
es. Six DIP switches, located under the belt
clip, facilitate selection of key parameters
including microphone preamplifier gain,
headphone output mode, talkback button
mode, and sidetone operation. Two of the
DIP switches are used to select the gain
of the microphone preamplifier from among
four choices. This allows the Model 380
to match the output sensitivity of a range
of handheld and headset-associated
microphones.
Using two DIP switches the headphone out-
put mode can be configured from among
four choices. The level/level mode is pro-
vided for broadcast applications where
two channels of talent cueing (“IFB”) need
to be independently sent to the left and
right headphone output channels. In on-air
sports events it’s typical for program audio
with director interrupt to be sent to the left
headphone output while program-only au-
dio is sent to the right headphone output.
The level/balance mode is intended for
applications where a stereo signal is being
routed to the Model 380’s Dante inputs.
In this mode the user is provided with one

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potentiometer to control the overall level
of both headphone output channels and
a second potentiometer to control the left/
right level balance.
The dual-channel monaural mode allows
the two Dante input audio channels to be
summed (mixed together) and sent to
both the left and right headphone output
channels.
Lastly, a unique single-channel monaural
mode is provided for on-air talent cue ap-
plications where a single-channel earpiece
or earbud is being used. The two Dante
audio input channels are mixed and sent
only to the left channel of the headphone
output. No audio signal is present on the
headphone output’s right channel.
The pushbutton switch, located on the
Model 380’s top panel, can be configured
to operate in either a momentary or latch-
ing mode. While the functional differences
are somewhat subtle, the two modes allow
distinct applications to be supported. In the
momentary mode the button can provide a
combination talkback function. This would
be applicable for on-air sports applica-
tions where the microphone signal typically
remains active. In the latching mode the
button could be considered as serving as
a microphone-on/off control. This would be
useful in applications where talent requires
local control of their microphone on and off
status.
The integrated sidetone function can be
enabled or disabled as required. This is
important as different applications may, or
may not, provide “mix-minus” talent cue
signals. In the case where no mix-minus
signal is present, providing a Model 380
user with sidetone is an important means
of confirming their local microphone audio.
Ethernet Data and PoE
The Model 380 connects to an Ethernet
data network using a standard 100 Mb/s
twisted-pair Ethernet interface. The physi-
cal interconnection is made by way of a
Neutrik® etherCON RJ45 connector. While
compatible with standard RJ45 plugs,
etherCON allows a ruggedized and lock-
ing interconnection for harsh or high-
reliability environments. An LED displays
the status of the network connection.
The Model 380’s operating power is
provided by way of the Ethernet interface
using the 802.3af Power-over-Ethernet
(PoE) standard. This allows fast and
efficient interconnection with the associ-
ated data network. To support PoE power
management, the Model 380’s PoE inter-
face reports to the power sourcing equip-
ment (PSE) that it’s a class 1 (very low
power) device. If a PoE-enabled Ethernet
port can’t be provided by the associated
Ethernet switch a low-cost PoE midspan
power injector can be utilized.
Future Capabilities and
Firmware Updating
The Model 380 was designed so that
its capabilities and performance can be
enhanced in the future. A USB connector,
located on the unit’s main circuit board
(underneath the unit’s cover), allows the
application firmware (embedded software)
to be updated using a USB flash drive.
The Model 380 uses Audinate’s Ultimo™
integrated circuit to implement the Dante
interface. The firmware in this integrated
circuit can be updated via the Ethernet
connection, helping to ensure that its
capabilities remain up to date.

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Getting Started
What’s Included
Included in the shipping carton are a
Model 380 On-Air Beltpack and a printed
copy of this guide. As a device that is
Power-over-Ethernet (PoE) powered,
no external power source is provided.
Should a PoE midspan power injector be
required it must be purchased separately.
Connections
In this section signal interconnections
will be made using the four connectors
located on the bottom of the Model 380’s
enclosure. An Ethernet data connection
with Power-over-Ethernet (PoE) capability
will be made using either a standard RJ45
patch cable or an etherCON protected
RJ45 plug. A microphone will be connect-
ed using a cable-mounted 3-pin male XLR
connector. A set of headphones or an
earpiece will be connected by way of
a ¼-inch 2- or 3-conductor plug. And,
depending on the application, the Model
380’s microphone-level output may be
interfaced with other equipment using
a cable terminated with a standard 3-pin
female XLR connector.
Ethernet Connection with PoE
A 100BASE-TX Ethernet connection that
supports Power-over-Ethernet (PoE) is
required for Model 380 operation. This one
connection will provide both the Ethernet
data interface and power for the Model
380’s circuitry. A 10BASE-T connection
is not sufficient and a 1000BASE-T
(“GigE”) connection is not supported
unless it can automatically “fall back”
to 100BASE-TX operation. The Model
380 supports Ethernet switch power
management, enumerating itself as a PoE
class 1 device.
The Ethernet connection is made by way
of a Neutrik etherCON protected RJ45
connector that is located on the bottom
of the Model 380’s enclosure. This allows
connection by way of a cable-mounted
etherCON connector or a standard RJ45
plug. The Model 380’s Ethernet interface
supports auto MDI/MDI-X so that a “cross-
over” or “reversing” cable will never be
required.
Ethernet Connection without PoE
As previously discussed in this guide,
the Model 380 was designed such that
the Ethernet connection will provide both
data and Power-over-Ethernet (PoE)
power. There may be situations where the
associated Ethernet switch does not pro-
vide PoE power. In such cases an external
PoE midspan power injector can be used.
If the selected midspan power injector is
802.3af-compatible it should function cor-
rectly. Midspan units are available from a
variety of sources, including many online
retailers.
Microphone Input
The Model 380 provides a 3-pin female
XLR connector that allows a balanced
dynamic microphone to be connected.
The microphone can be a standalone
handheld (“stick”) type or can be part of a
broadcast-style headset. The Model 380’s
microphone input is directly compatible
with balanced dynamic microphones. A
microphone should be connected such
that pin 1 is common, pin 2 is signal high
(+), and pin 3 is sign low (–).
It’s possible to connect a microphone
that requires P12 or P48 phantom power

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Page 10 Studio Technologies, Inc.
for operation. In this case power must be
provided externally by way of a compatible
signal connection made to the Model 380’s
microphone output connector. It’s expected
that the microphone output connector would
interface with the microphone input on a
broadcast camera, audio console, micro-
phone mixer, or similar equipment. Inputs
on these devices would typically offer phan-
tom power and they should be enabled.
Phantom power present on the Model 380’s
microphone output will “pass through” to
the Model 380’s microphone input and then
on to the connected microphone. The Mod-
el 380’s microphone input circuitry will not
be damaged by the presence of phantom
power. It will still function properly, offering
the same performance as if a dynamic mi-
crophone was connected to the Model 380’s
microphone input.
Headphone Output
The Model 380 provides a 2-channel
headphone output by way of a 3-conduc-
tor ¼-inch phone jack. Devices such as
stereo headphones or stereo (“dual-muff”)
broadcast-style headsets can be directly
connected using a 3-conductor ¼-inch plug.
Following the usual convention the left
channel should be terminated on the tip
lead, the right channel on the ring lead,
and common on the sleeve lead.
It’s also possible to use a monaural (“single-
muff”) headset or broadcast-type single
earbud but some care must be taken. If
a 3-conductor ¼-inch plug is used by the
device it should be wired to the tip and
sleeve leads; the plug’s ring lead should
be left unconnected. But it’s also very likely
that the monaural device will be terminated
on a 2-conductor (“tip and sleeve”) plug.
When the plug is inserted into the Model
380’s headphone jack the Model 380’s right
headphone output channel will be short-
ed; the ring lead will be directly shorted to
the sleeve lead. This can lead to stress on
the right channel headphone output cir-
cuitry as well as extra current draw. To pre-
vent this condition the headphone output
mode configuration choice should be set
for single-channel monaural. This disables
the right headphone output channel and
sends the listen audio sources only to the
left output channel. Refer to the Configura-
tion section later in this guide for details
on setting the headphone audio routing.
Microphone Output
A 3-pin male XLR connector provides a
microphone-level output that’s directly re-
lated to the microphone input. Technically
the output is identical to the signal that’s
connected to the microphone input but
with a solid-state muting circuit in series
with the interconnection. When the Model
380’s Dante main output channel is active
the microphone signal passes through
to the Model 380’s microphone output.
When the main output channel is muted
(and the Dante talkback channel is ac-
tive) the microphone signal does not pass
through to the microphone output; it’s is
muted in an essentially click-free manner.
Refer to Appendix A, located at the end
of the guide, for a block diagram of the
microphone input and microphone output
circuitry. Studying this diagram can help
illuminate one of the more unique Model
380 features.
The microphone output can be connected
to a balanced (differential) analog micro-
phone-level input on a variety of devices.
When the Model 380 was designed the
primary target devices were portable
ENG-style video cameras that included
microphone inputs. The mic inputs on

Model 380 User Guide Issue 2, February 2017
Studio Technologies, Inc. Page 11
these cameras are typically amplified and
then embedded with the video signal into
an SDI output. This would ensure that
“lip sync” would be maintained since the
audio and video would travel on the same
digital stream. The Model 380’s Dante
main output channel would not be used or
would only be used as a backup path. The
microphone output can also be connected
to mic inputs on audio consoles or to con-
sole remote I/O interfaces, e.g., Calrec®
Hydra2®.
No preamplifier or other active circuitry
impacts the path from the Model 380’s
microphone input connector to the Model
380’s microphone output connector. The
signal does pass through a 200 ohm resis-
tor in each “leg” (pin 2 and pin 3) along
with connecting to a solid-state relay
contact. The result is that the source
impedance of a connected microphone
will be 400 ohms greater when presented
to the microphone output. This will slightly
raise the theoretical noise floor of the
microphone signal vis-a-vis the micro-
phone output but shouldn’t have any
impact on real-world applications.
As previously discussed, if the connected
microphone requires P12 or P48 phantom
power it must be provided by way of a
connection made to the Model 380’s
microphone output connector. The phan-
tom power will “pass through” to the
Model 380’s microphone input connector
and on to a connected microphone. The
state of the muting circuitry (muted or
not muted) will not impact the phantom
power source. The series resistance
(approximately 200 ohms in each leg
of the balanced signal) should also not
impact the phantom power being provided
to a connected microphone.
Dante Configuration
For audio to pass to and from the Model
380 requires that several Dante-related
parameters be configured. These configu-
ration settings will be stored in non-volatile
memory within the Model 380’s circuitry.
Configuration will typically be done with
the Dante Controller software application
which is available for download free of
charge at www.audinate.com. Versions
of Dante Controller are available to sup-
port Windows® and OS X® operating
systems. The Model 380 uses the Ultimo
2-input/2-output integrated circuit to imple-
ment the Dante architecture.
The two Dante transmitter (Tx) channels
associated with the Model 380’s Dante
interface must be assigned to the desired
receiver channels. This achieves routing
the Model 380’s two output audio chan-
nels to the device (or devices) that will
be “listening” to them. Within Dante
Controller a “subscription” is the term
used for routing a transmitter flow (a
group of output channels) to a receiver
flow (a group of input channels). The
number of transmitter flows associated
with an Ultimo integrated circuit is limited
to two. These can either be unicast,
multicast, or a combination of the two.
If the Model 380’s transmitter channels
need to be routed to more than two flows
it’s possible that an intermediary device,
such as a rack-mounted digital signal
processor unit with more available flows,
can be used to “repeat” the signals.
The two Dante receiver (Rx) channels
associated with the Model 380’s audio
inputs also need to be routed to the de-
sired Dante transmitter channels. These
two audio signals will be sent to the Model
380’s 2-channel headphone output.

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The Model 380 supports audio sample
rates of 44.1 and 48 kHz with a limited
selection of pull-up/pull-down values
available. In most cases the default will
be used and a pull-up or pull-down rate
will not be selected. The Model 380 can
serve as the clock master for a Dante
network but in most cases it will be config-
ured to “sync” to another device.
The Model 380 has a default Dante device
name of ST-M380 and a unique suffix.
The suffix identifies the specific Model 380
that is being configured. The suffix’s actual
alpha and/or numeric characters relate to
the MAC address of the unit’s Ultimo inte-
grated circuit. The two Dante transmitter
(Tx) channels have default names of
Main and Talkback. The two Dante re-
ceiver (Rx) channels have default names
of Headphone Ch1 and Headphone Ch2.
Using Dante Controller the default device
name and channel names can be revised
as appropriate for the specific application.
Model 380 Configuration
The Model 380 provides six DIP switches
which are used to configure four operat-
ing functions. These allow the unit to be
optimized to match the needs of specific
applications. Two of the switches allow the
gain of the microphone preamplifier to be
adjusted. Two switches select how incom-
ing audio and sidetone audio are routed to
the headphone output channels. The fifth
switch selects the mode of the talkback
button. The sixth switch selects the on/off
status of the sidetone function. Physically
the switches are accessible from the back
of the Model 380’s enclosure through a
rectangular opening that is located under
the top of the belt clip.
The DIP switches are connected to the
Model 380’s logic circuitry which responds
to changes by way of the application firm-
ware; no audio passes directly through the
switches. Changes made to a DIP switch
will immediately be reflected in the unit’s
operation.
Accessing the Configuration Switches
To access the six configuration DIP switch-
es requires that the belt clip be rotated.
Normally the belt clip is secured to the
back of the enclosure using one rivet
(non-removable) and one machine screw
that has a thread pitch of 6-32. To allow
the belt clip to rotate, remove the machine
screw using a #1 Phillips head screw
driver. The belt clip should now be able to
rotate in either direction. Save the screw
so that it can be re-installed once the
desired configuration choices have been
made. Note that the threaded fastener
within the back of the Model 380’s chas-
sis has an internal locking mechanism
(a plastic bushing) that prevents the belt
clip’s 6-32 machine screw from vibrating
loose. So no additional method of thread
locking, such as a lock washer or chemi-
cal compound, is necessary.
Microphone Preamp Gain
Switches SW1 and SW2 allow the gain of
the Model 380’s microphone preamplifier
to be selected. When SW1 and SW2 are
in their down (off) position 35 dB of gain is
selected. Placing SW1 to its up (on) posi-
tion while leaving SW2 in its down (off)
position selects the 43 dB gain setting.
Leaving SW1 to its down (off) position
while placing SW2 in its up (on) position
selects the 52 dB gain setting. Placing
SW1 and SW2 to their up (on) positions
selects the gain to be 59 dB.

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Studio Technologies, Inc. Page 13
The compressor active LED, visible on the
bottom of the Model 380’s enclosure adja-
cent to the mic input connector, can act as
a guide when setting the preamp gain.
During normal talk operation the compres-
sor active LED should light intermittently.
If, for example, it rarely lights and the gain
is set to 43 dB, it might be a good idea to
change to setting to 52 dB. If the LED is
lit fully during normal talking and the gain
is set for 52 or 59 dB, changing it to one
of the lower values might be warranted.
There’s no “hard and fast” rule about which
gain setting is appropriate. But unless oth-
erwise indicated, 43 dB is typically a good
initial choice.
Headphone Output Mode
Switches SW3 and SW4 allow selection
from four headphone output operating
modes. Each mode is distinct and careful
selection will help optimize the Model 380’s
operation for a range of applications.
Level/Level
The level/level mode is provided for on-
air applications where two independent
audio sources need to be routed to sepa-
rate headphone output channels. Dante
audio input channel 1 will be routed to the
left headphone output channel and top-
panel left phones potentiometer will adjust
its level. Dante audio input channel 2 will
be routed to the right headphone output
channel and right phones potentiometer
will adjust its level.
Level/Balance
The level/balance mode is provided for
stereo applications such as live music
events or radio broadcasts. In these appli-
cations it’s typical to want the user to have
a single control to simultaneously adjust
the level of both channels; a separate
control will be used to adjust the left/right
level balance.
When set for the level/balance mode
Dante input channel 1 will be routed to the
headphone left output channel and Dante
input channel 2 will be routed to the right
output channel. The left phones potenti-
ometer will adjust the overall level on both
headphone output channels. The right
phones potentiometer will adjust the level
balance between the left and right output
channels.
Dual-Channel Monaural
The dual-channel monaural mode can
be useful in applications where the same
audio signals need to be provided to the
user on both the left and right headphone
output channels. In this mode Dante audio
inputs 1 and 2 are routed to both the left
and right channels of the headphone out-
put. The left phones potentiometer adjusts
the level of input 1 and the right phones
potentiometer adjusts the level of input 2.
Single-Channel Monaural
The single-channel monaural mode is spe-
cifically provided for applications where a
Figure 2. Microphone preamplifier gain
configuration switches

Issue 2, February 2017 Model 380 User Guide
Page 14 Studio Technologies, Inc.
2-conductor 1/4-inch or 3.5 mm plug is be-
ing used with the connected headphones,
headset, or a broadcast-style earpiece. In
this mode Dante audio inputs 1 and 2 are
mixed together and routed to the left chan-
nel of the headphone output; no audio
signal is routed to the right channel of the
headphone output. The left phones poten-
tiometer adjusts the level of input 1 and
the right phones potentiometer adjusts the
level of input 2.
Talkback Button Mode
Switch SW5 is used to configure the
talkback button mode to be either mo-
mentary or latching. In the momentary
mode the Dante main output channel and
microphone output will be active and the
button’s green LED will be lit. When the
button is pressed and held the LED will
turn orange, the Dante main output chan-
nel and microphone output will mute, and
the Dante talkback output channel will
become active. When the button is re-
leased the function will return to the origi-
nal state. When selected for the latching
mode tapping (momentarily pressing) the
button will cause the function to change
states, moving between the Dante main
output channel and microphone output
being active and the Dante talkback out-
put channel being active.
Figure 4. Talkback button mode configuration
switch
Figure 3. Headphone output mode configuration switch

Model 380 User Guide Issue 2, February 2017
Studio Technologies, Inc. Page 15
Sidetone
Switch SW6 allows the sidetone function
to be enabled or disable as desired.
Selecting the on or off mode for sidetone
will depend on the needs of the applica-
tion. If a “full mix” is being provided to the
Model 380 then locally provided sidetone
won’t need to be provided. The user will
hear themselves by way of the audio sig-
nals being routed to the Dante input audio
channels. But if a “mix-minus” is being
supplied to the Model 380 then having
sidetone enabled will be important as a
user confidence monitor.
In this way the unit’s two audio output
channels (Dante transmitter channels) and
two audio input channels (Dante receiver
channels) should have been routed to
the receiver and transmitter channels
on associated equipment. The Model
380’s configuration switches should have
been set to meet the needs of the specific
application.
Initial Operation
The Model 380 will start to function as
soon as a Power-over-Ethernet (PoE)
power source is connected. However,
it may take 20 to 30 seconds for full
operation to commence. Upon initial
power up the three status LEDs located
on the bottom panel below the RJ45 jack
will begin to light as network and Dante
connections are established. The green
and orange LED backlights within the
talkback pushbutton switch will light in a
quick test sequence to indicate that the
main operating firmware (embedded soft-
ware) has started. Once the sequence has
completed and the Dante connection has
been established full operation will begin.
Ethernet and Dante Status
LEDs
Three status LEDs are located below the
etherCON RJ45 connector on the Model
380’s bottom panel. The LINK ACT LED
will light green whenever an active con-
nection to a 100 Mb/s Ethernet network
has been established. It will flash in re-
sponse to Ethernet data packet activity.
The SYS and SYNC LEDs display the
operating status of the Dante interface
and associated network. The SYS LED
will light red upon Model 380 power up
to indicate that the Dante interface is not
Figure 5. Sidetone function configuration switch
Operation
At this point everything should be ready
and Model 380 operation can commence.
An Ethernet connection with Power-over-
Ethernet (PoE) capability should have
been made. Alternately, a midspan power
injector, in “series” with the Ethernet
connection, should have been put into
place. A microphone and headphones
or earbud should have been connected.
Alternately, a broadcast-style headset
should be connected. If desired, a con-
nection to the microphone output should
have been made.
The Model 380’s Dante configuration
settings should have been selected using
the Dante Controller software application.

Issue 2, February 2017 Model 380 User Guide
Page 16 Studio Technologies, Inc.
ready. After a short interval it will light
green to indicate that it is ready to pass
data with another Dante device. The SYNC
LED will light red when the Model 380 is
not synchronized with a Dante network. It
will light solid green when the Model 380
is synchronized with a Dante network and
an external clock source (timing reference)
is being received. It will slowly flash green
when the Model 380 is part of a Dante
network and is serving as a clock master.
It’s possible that up to 30 seconds may
be required for the SYNC LED to reach
its final state.
How to Identify a Specific
Model 380
The Dante Controller software applica-
tion offers an identify command that can
be used to help locate a specific Model
380. When identify is selected it will send
a command to a single Model 380 unit.
On that specific unit the talkback push-
button’s orange LED will flash on and off
approximately eight times. (The on/off
status of the button will not change.) In
addition, the SYS and SYNC status LEDs,
located directly below the etherCON RJ45
connector on the bottom panel, will slowly
flash green. After a few seconds the LED
identification pattern will cease and normal
Model 380 button LED and Dante status
LED operation will resume.
Headphone Listen Level
Three rotary potentiometers (pots),
located on the Model 380’s top panel,
allow adjustment of the level of the two
audio input signals and sidetone as they
are sent to the 2-channel headphone
output. How the pots function will depend
on how the headphone output has been
configured. Four modes are available and
allow unique output performance. In the
level/level mode the left phones pot will
control the level of Dante input 1 as it is
being sent to the left channel of the head-
phone output. The right phones pot will
control the level of Dante input 2 as it is
sent to the right output. Sidetone audio,
if enabled, will be sent to both the left and
right output channels.
In the level/balance mode the left phones
pot will adjust the level of both the left
and right headphone outputs. The right
phones pot will control the left/right level
balance of the headphone output. Side-
tone audio, if enabled, will be sent to both
the left and right output channels.
When dual-channel monaural mode has
been selected the left phones pot will ad-
just the level of Dante input 1 as it is rout-
ed to both the left and right headphone
output channels. The right phones pot
will adjust the level of Dante input 2 as it
is sent to both the left and right head-
phone outputs. Sidetone audio, if enabled,
will be sent to both the left and right out-
put channels.
When the Model 380 has been configured
for the single-channel monaural mode the
left phones pot adjusts the level of Dante
input 1 as it is routed to the left channel of
the headphone output. The right phones
pot will adjust the level of Dante input 2 as
it is also routed only to the left headphone
output channel. In this mode no signal
will be present on the right channel of
the headphone output. Sidetone audio,
if enabled, will be sent only to the left
output channel.

Model 380 User Guide Issue 2, February 2017
Studio Technologies, Inc. Page 17
The pots are “push-in/push-out” type
which allow their associated knobs to be
in their “out” position to be adjusted and
their “in” position when protection from an
unwanted change is desired. When a pot
is in its fully counterclockwise position the
associated audio signal is fully muted.
Users should find the headphone output
audio quality to be excellent, with high
maximum output level and low distortion.
Analog audio signals do not pass directly
through the level pots. The position of the
pots is recognized by the Model 380’s
processor which then adjusts the signal
level within the digital domain.
Compressor Active LED
A yellow LED indicator is located on the
bottom panel adjacent to the mic input
connector. Labeled COMP, the LED dis-
plays the status of the microphone audio
compressor function. It will light whenever
the input level from the microphone, along
with the configured mic preamp gain, is
such that the dynamic range of the talk
signal is being controlled. It’s perfectly ac-
ceptable for this LED to light intermittently
whenever a user is talking at a normal
voice level into the associated micro-
phone. But if the COMP LED lights solid
while a user is talking at a normal voice
level this will typically indicate that the mic
gain setting should be reduced. Converse-
ly, if the COMP LED almost never lights
when normal talking is taking place, it’s
possible that changing the gain to a high-
er value would be beneficial. Note that due
to the design of the circuitry the compres-
sor active LED will function whether or not
any of the four talk channels are active.
Talkback Button
One pushbutton switch is used to select
the status of the two Dante audio output
channels and the microphone output con-
nector. Labeled TALKBACK, the button
really provides both an output mute and a
talkback enable function. When “talkback”
is active audio is no longer sent out the
Dante main output channel but instead
is routed to the Dante talkback output
channel. In this way the “on-air” channel
is muted and the talkback channel is ac-
tive. And whenever the Dante main output
channel is muted the microphone output,
provided on the 3-pin XLR connector, will
also be muted. How the talkback button
will specifically function will depend on the
configuration of the Model 380.
Momentary
When the talkback button has been
configured for momentary operation
how it functions is pretty self-explanatory.
Press and hold the button to enable the
talkback function. When talkback is en-
abled microphone audio will be sent out
the Dante talkback output channel; the
Dante main output channel and the micro-
phone output will both be muted. When
the talkback button is pressed the button’s
orange LED will light. When the talkback
button is not pressed the button’s green
LED will be lit.
Latching
If the talkback button has been configured
for the latching mode its operation is a bit
different. Momentarily pressing (“tapping”)
the button will cause the talkback func-
tion to change states: off-to-on or on-to-
off. Whenever microphone audio is being
sent out the Dante main output channel

Issue 2, February 2017 Model 380 User Guide
Page 18 Studio Technologies, Inc.
and the microphone output is active the
button’s green LED will be lit. The button’s
LED will light orange when the talkback
function is enabled and microphone audio
is being sent out the Dante talkback out-
put channel while both the Dante main
output channel and microphone output
are muted.
Sidetone Function
The Model 380 includes a sidetone func-
tion that sends microphone audio to the
headphone output whenever the micro-
phone audio is being sent to the Dante
main output channel and the microphone
output. Sidetone audio will never be pro-
vided when the talkback function is active.
Sidetone audio quality should be excellent
and will provide the Model 380 user with
a confidence signal that they are active or
“on-air.” A configuration choice allows the
sidetone function to be enabled or dis-
abled as desired for the application. In a
nutshell, if a mix-minus cue signal is being
provided to the user by way of the audio
inputs then sidetone will typically want to
be enabled.
Whether sidetone audio will be sent to the
left and right headphone output channels
or only the left headphone output chan-
nel will depend on the configuration of the
headphone output. As expected, when the
headphone output mode is configured for
level/level, level/balance, or dual-channel
monaural, sidetone audio will be sent to
the left and right headphone output chan-
nels. When configured for single-channel
monaural, sidetone audio will be sent only
to the left headphone output channel.
The level of sidetone audio being sent
to either the left and right headphone out-
put channels or only the left headphone
output channel is adjusted using the rotary
level control (pot) that is located on the
top of the Model 380’s enclosure. Typically
providing a precise sidetone level is not
important and most users will not be con-
cerned about setting it to a specific value.
But setting the sidetone level to something
reasonable is important. Setting the level
too low will encourage a user to speak
too loudly; setting it too high and the user
will be tempted to speak hesitantly. Audio
does not pass directly through the side-
tone pot. The pot’s position is monitored
by the Model 380’s processor which then
controls the level within the digital audio
domain.
Technical Notes
IP Address Assignment
By default the Model 380’s Ethernet inter-
face will attempt to automatically obtain an
IP address and associated settings using
DHCP (Dynamic Host Configuration Pro-
tocol). If a DHCP server is not detected an
IP address will automatically be assigned
using the link-local protocol. This proto-
col is known in the Microsoft® world as
Automatic Private IP Addressing (APIPA).
It is also sometimes referred to as auto-IP
(PIPPA). Link-local will randomly assign
a unique IP address in the IPv4 range of
169.254.0.1 to 169.254.255.254. In this
way multiple Dante-enabled devices can
be connected together and automatically
function, whether or not a DHCP server
is active on the LAN. Even two Dante-
enabled devices that are directly inter-
connected using an RJ45 patch cord
will, in most cases, correctly acquire IP
addresses and be able to communicate
with each other.

Model 380 User Guide Issue 2, February 2017
Studio Technologies, Inc. Page 19
An exception does arise when trying to
directly interconnect two Dante-enabled
devices that use Ultimo integrated circuits
to implement Dante. The Model 380 uses
the Ultimo “chip” and, as such, a direct
one-to-one interconnection to another
Ultimo-based product is not supported.
An Ethernet switch linking the two units is
required to successfully interconnect two
Ultimo-based devices. The technical rea-
son that a switch is required relates to the
need for a slight latency (delay) in the data
flow; an Ethernet switch will provide this.
Using the Dante Controller software ap-
plication the Model 380’s IP address and
related network parameters can be set for
a fixed (static) configuration. While this is
a more involved process than simply let-
ting DHCP or link-local “do their thing,”
if fixed addressing is necessary then this
capability is available. But in this case it’s
highly recommended that every unit be
physically marked, e.g., directly using
a permanent marker or “console tape,”
with its specific static IP address. If knowl-
edge of a Model 380’s IP address has
been misplaced there is no reset button
or other method to easily restore the unit
to a default IP setting.
In the unfortunate event that a device’s
IP address is “lost,” the Address Resolu-
tion Protocol (ARP) networking command
can be used to “probe” devices on a
network for this information. For example,
in Windows OS the arp –a command can
be used to display a list of LAN informa-
tion that includes MAC addresses and
corresponding IP addresses. The simplest
means of identifying an unknown IP ad-
dress is to create a “mini” LAN with
a small PoE-enabled Ethernet switch
connecting a personal computer to the
Model 380. Then by using the appropriate
ARP command the required “clues” can
be obtained.
Optimizing Network
Performance
For best Dante audio-over-Ethernet perfor-
mance a network that supports VoIP QoS
capability is recommended. This can typi-
cally be implemented on virtually all con-
temporary managed Ethernet switches.
There are even specialized switches that
are optimized for entertainment-associated
applications. Refer to the Audinate website
(www.audinate.com) for details on optimiz-
ing networks for Dante applications.
Application Firmware Version
Display
As part of the Model 380’s power-up
sequence the unit’s application firmware
(embedded software) version number can
be displayed. This is useful when working
with factory personnel on application sup-
port and troubleshooting. Before connect-
ing the PoE-enabled Ethernet cable, press
and hold the talkback button. Then con-
nect the Ethernet cable. Upon application
of PoE power the Model 380 will not go
through its normal power-up sequence but
instead will display the firmware version.
The LED associated with the talkback
button will “flash” green in color to display
the major version number and then “flash”
orange to display the minor version num-
ber. Then the LED will remain off until the
talkback button is released. Once the but-
ton has been released normal operation
will then take place. As an example
of what would be a typical firmware dis-
play, if the talkback button’s LED “flashes”
green once followed by the LED “flashing”

Issue 2, February 2017 Model 380 User Guide
Page 20 Studio Technologies, Inc.
orange thrice it would indicate that applica-
tion firmware version 1.3 is present in the
Model 380.
Application Firmware Update
Procedure
It’s possible that updated versions of the
application firmware (embedded software)
that is utilized by the Model 380’s proces-
sor (microcontroller or MCU) integrated
circuit will be released to add features or
correct issues. Refer to the Studio Tech-
nologies website for the latest application
firmware file. The unit has the ability to load
a revised file into the MCU’s non-volatile
memory by way of a USB interface. The
Model 380 implements a USB host function
that directly supports connection of a USB
flash drive. The Model 380’s MCU updates
its firmware using a file named m380.bin.
The update process begins by preparing
a USB flash drive. The flash drive doesn’t
have to be empty (blank) but must be in
the personal-computer-standard FAT32 for-
mat. Save the new firmware file in the root
directory with a name of m380.bin. Studio
Technologies will supply the application
firmware file inside a .zip archive file. While
the firmware file inside of the zip file will ad-
here to the naming convention required by
the Model 380, the name of the zip file itself
will include the file’s version number. For
example, a file named m380v1r3MCU.zip
would indicate that version 1.3 of the ap-
plication firmware (m380.bin) is contained
within this zip file.
Once the USB flash drive is inserted into
the USB interface, located on the main
circuit board under the cover, the unit
must be powered off and again powered
on. At this point the file will automatically
load. The precise steps required will be
highlighted in the next paragraphs of
this guide. After the firmware has been
updated the LED associated with the talk-
back button should be used to confirm
that the desired application firmware
version has been successfully installed.
To install the application firmware file
follow these steps:
1. Disconnect power from the Model 380.
This will entail removing the Ethernet
connection that is providing PoE power.
2. Remove the cover from the Model 380.
Begin by removing the four Phillips
head screws (#1 screw driver tip), two
per side. Be certain to save the screws
so that re-assembly will be fast and
painless. Then carefully slide the cover
forward to separate it from the level
controls and buttons and then lift it off.
3. Locate the USB connector on the main
circuit board. It’s near the front of the
unit, directly between the channel 1 and
channel 2 rotary level controls. Insert
the prepared USB flash drive into it.
4. Apply power to the Model 380 by
connecting to a Power-over-Ethernet
(PoE) Ethernet source.
5. After a few seconds the Model 380 will
run a “boot loader” program that will
automatically load the new application
firmware file (m380.bin). This loading
process will take only a few seconds.
During this time period the talkback
button LED will flash slowly in alternate
colors. Once the entire loading process
is over, taking approximately 10 sec-
onds, the Model 380 will restart using
the newly-loaded application firmware.