Studio Technologies 208 User Manual

Model 208 Announcer’s Console

User Guide

Issue 2, October 2018

This User Guide is applicable for serial numbers

M208-00151 and later with application firmware 1.4 and later

Copyright © 2018 by Studio Technologies, Inc., all rights reserved

www.studio-tech.com

50651-1018, Issue 2

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MODEL 208

ANNOUNCER’S CONSOLE

Table of Contents

Revision History ........................................................... 4

Introduction ................................................................... 5

Getting Started ............................................................. 9

Operation ...................................................................... 18

Technical Notes ............................................................ 24

Specifications ............................................................... 28

Appendix A: Views of Model 208 with Optional

MBK-02 Mounting Brackets .......................................... 29

Appendix B: Model 208 Block Diagram ........................ 30

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Revision History

Issue 2, October 2018:

• Documents addition of the Push to Mute/Tap to Latch mic on/off button mode.

Issue 1, January 2018:

• Initial release.

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Introduction

The Model 208 Announcer’s Console
offers a unique combination of analog and
digital audio resources for use in broadcast
sports, eSports, live event, entertainment,
and streaming broadcast applications.
The unit is housed in a compact enclosure
that’s intended for table-top use. Optional
mounting brackets provide a simple means
of integrating the Model 208 into a variety
of broadcast furniture or on-air sets. The
Model 208 supports Dante® audio-over­Ethernet digital media technology as well
as AES67 for integration into contemporary
applications. The unit is extremely simple
to deploy, is “pro” quality throughout, and
provides an intuitive user experience. The
Model 208’s audio quality is excellent,
with low distortion, low noise, and high
headroom. Careful circuit design and
rugged components ensure long, reliable
operation.

The Model 208 integrates directly into both
Dante audio-over-Ethernet and standard
analog audio environments. With just a
Power-over-Ethernet (PoE) connection, a
microphone, and a pair of headphones or
an earpiece, a complete broadcast on-air
position can be created. And by using the
Model 208’s microphone output a direct
connection to an analog microphone-level
input on an associated camera, remote I/O

interface, or audio console can be support­ed. Contact inputs allow external signals
to work in conjunction with the mic on/off
button and talkback button functions.

Key Model 208 features are configured
using the STcontroller personal computer
software application. An extensive set of
parameters allows the unit’s operation
to be tailored to meet the needs of many
applications. STcontroller, compatible with
version 7 and later of the Windows® oper­ating system, is a fast and simple means
of confirming and revising the unit’s oper­ating parameters.

Applications

The Model 208 on its own can provide an
“all-Dante” solution for one on-air talent
location. A wide range of applications can
be supported, including sports and enter­tainment TV and radio events, streaming
broadcasts, corporate and government AV
installations, and post-production facilities.
Two Dante receiver (audio input) channels
supply the user with their talent cue (IFB)
signals. Should the cue signal be “mix­minus” an integrated sidetone function
can provide the user with a microphone
confidence signal. Two Dante audio output
channels, one designated as main (for on­air) and the other talkback, are routed via
an associated local-area network (LAN)
to inputs on Dante-compatible devices.

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Figure 1. Model 208 Announcer’s Console front and rear views

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Two pushbutton switches, microphone
on/off and talkback, provide the user with
direct control over audio routing. The audio
switching is performed in the digital do­main and is virtually “click-free.”

By providing the main (on-air) audio sig­nal in two forms, Dante digital audio and
analog microphone level, the Model 208
makes integration into a wide range of
environments easy to accomplish. And
with the talkback audio available as a
Dante output channel, routing to inputs
on a variety of devices, such as matrix
intercom systems, audio consoles, and
monitor loudspeaker systems, is simple
and flexible.

Some applications may benefit from not
utilizing the Model 208’s Dante main out­put channel. This typically won’t be an is­sue of inadequate audio quality but rather
a need to match work-flow requirements.
For example, for lip-sync or transmission
purposes it may be optimal to have the
on-air audio transported as an embedded
signal along with the associated 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 scenarios is not a problem
as the Model 208 supplies a microphone
output connection that’s specifically intend­ed for this purpose. Simply connect the
unit’s microphone 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
208’s analog 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
microphone output connector whenever
the microphone output is off or the talk­back function is active. And it’s important
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 backup, secondary,
or redundant on-air audio signal.

Setup and Operation

Set up, configuration, and operation of
the Model 208 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 broadcast
headset or handheld (“stick”) microphone
can be directly connected to the unit’s
3-pin XLR mic input connector. The input
is compatible with a dynamic or condenser
microphone. The integrated P48 phantom
power source allows operation with
a wide range of condenser microphones.
A 3-pin XLR mic output connector provides
a “direct mic out” function for integration
with mic inputs on related devices. Stereo
headphones, the headphone connections
from a stereo or monaural headset, or
even a monaural earpiece can be con­nected to the phones output jack. External
switches can be connected to the Model
208 to allow remote control of the button
functions. The STcontroller software
application is used to configure the wide
range of Model 208 operating parameters.
This allows the unit’s performance to be
optimized to meet the needs of specific
applications.

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The user is presented with two pushbut­ton switches and three “push-in/push-out”
rotary level controls. This makes it easy to
control the status of the microphone and
talkback outputs as well as adjusting the
signals that are sent to the headphone
channels.

two in each direction. The digital audio’s
bit depth is up to 24 with a sampling rate
of 44.1, 48, 88.2, or 96 kHz. Two bi-color
LEDs provide an indication of the Dante
connection status. An additional LED dis­plays the status of the associated Ethernet
connection.

Ethernet Data and PoE

The Model 208 connects to a local area net­work (LAN) by way of a standard 100 Mb/s
twisted-pair Ethernet interface. The physical
100BASE-TX interconnection is made by
way of a Neutrik® etherCON RJ45 connec­tor. While compatible with standard RJ45
plugs, etherCON allows a ruggedized and
locking interconnection for harsh or high­reliability environments. An LED displays
the status of the network connection.

The Model 208’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 associated data net­work. To support PoE power management,
the Model 208’s PoE interface reports to the
power sourcing equipment (PSE) that it’s a
class 1 (very low power) device. If a PoE­enabled Ethernet port can’t be provided by
the associated Ethernet switch a low-cost
PoE midspan power injector can be utilized.

Dante Audio-over-Ethernet

Audio data is sent to and received from
the Model 208 using the Dante audio-over­Ethernet media networking technology. As
a Dante-compliant device, the Model 208’s
two output (Dante transmitter) and two input
(Dante receiver) audio channels can be as­signed to other devices (routed) using the
Dante Controller software application. The
Dante transmitter and receiver channels
are limited to supporting four Dante flows,

The Model 208 is compatible with the
AES67 interoperability standard. In this
mode the two transmitter (output) channels
will function in multicast; unicast is not sup­ported. In addition, the unit is compatible
with the Dante Domain Manager™ (DDM)
software application.

Audio Quality

The Model 208’s audio performance is
completely “pro.” A low-noise, wide dynam­ic-range microphone preamplifier and as­sociated voltage-controlled-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-to­digital conversion (ADC) section that sup­ports sampling rates of 44.1, 48, 88.2, and
96 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
208’s processor. The sampling rate will be

44.1, 48, 88.2, or 96 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 flexibility, allows precise control,
and keeps the three level potentiometers
(two for audio inputs and one for sidetone)
from having to directly handle analog audio

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signals. The two audio channels destined
for the phones outputs are sent to a high­performance 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

The Model 208 can be configured to meet
the needs of specific applications and user
preferences. All configuration choices are
performed using the STcontroller personal
computer software application which is
compatible with version 7 and later of the
Windows operating systems. There are no
mechanical switches settings or button­press sequences required to configure how
the unit functions. Selectable parameters
include microphone preamplifier gain, P48
phantom power on/off, button operation,
headphone output mode, sidetone opera­tion, and overall unit operation. The gain
of the microphone preamplifier can be
selected from among four choices. This
allows the Model 208 to match the out­put sensitivity of a range of handheld and
headset-associated microphones. A low­noise source of P48 phantom power can be
enabled if required to support a variety
of high-performance microphones.

The mic on/off and talkback pushbutton
switches, located on the Model 208’s front
panel, can be individually configured. The
mic on/off button can be selected to oper­ate from among five modes while the talk­back button can be selected from among
three. These choices allow the Model 208’s
operation to be tailored to meet the specific
needs of many applications. As an exam­ple, for on-air sports the mic on/off button
would typically be configured to provide a
push to mute (cough) function. The micro­phone signal would typically remain active

unless the talent needs to momentarily
disable it. The talkback button would most
likely be set in its push to talk mode as its
use would be intermittent.

The headphone output mode can be
configured from among four choices. The
level/level mode is provided 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 audio 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
208’s Dante inputs. In this mode the user
is provided with one 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 applications 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 integrated sidetone function can be
configured from among four choices. This
allows audio associated with the micro­phone input and microphone preamplifier
to be returned to the headphone output.
This is important as different applications
may provide a “full mix” or a “mix-minus”
talent cue signal. If a full mix cue signal is

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provided then sidetone audio will not be
needed and the function can be disabled.
In the case where a mix-minus signal is
present, providing the user with sidetone
can be an important means of confirming
the signal that’s coming from the connect­ed microphone.

The headphone gain range configura­tion helps to provide an optimized audio
level to Model 208 users. The appropriate
setting will depend on the specific audio
sources provided to the unit as well as
user preference.

Getting Started

What’s Included

Included in the shipping carton are a
Model 208 Announcer’s Console 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. For mounting on a flat surface the
optional bracket kit (Studio Technologies
order code MBK-02) should be ordered.

Three system modes select the overall
way in which the Model 208 functions. The
on-air mode is optimized for applications
where users will be on-air talent that must
maintain strict separation between on-air
and production audio channels. Other
applications will be benefit from the two
available production modes.

Future Capabilities and
Firmware Updating

The Model 208 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 208 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.

Connections

In this section signal interconnections will
be made using the five connectors located
on the back of the Model 208’s enclosure.
An Ethernet data connection with Power­over-Ethernet (PoE) capability will be
made using either a standard RJ45 patch
cable or an etherCON protected RJ45
plug. A microphone will be connected
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. If desired,
the Model 208’s microphone-level output
may be interfaced with other equipment
using a cable terminated with a standard
3-pin female XLR connector. Special ap­plications may utilize the remote control
inputs that are accessible using a 3.5 mm
3-conductor jack.

Ethernet Connection with PoE

A 100BASE-TX Ethernet connection that
supports Power-over-Ethernet (PoE) is
required for Model 208 operation. This one
connection will provide both the Ethernet
data interface and power for the Model
208’s circuitry. A 10BASE-T connection is
not sufficient and a 1000BASE-T (“GigE”)
connection is not supported unless it can

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automatically “fall back” to 100BASE-TX
operation. The Model 208 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 back of the
Model 208’s enclosure. This allows connec­tion by way of a cable-mounted etherCON
connector or a standard RJ45 plug. The
Model 208’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 208 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 provide
PoE power. In such cases an external PoE
midspan power injector can be used. If the
selected midspan power injector is 802.3af­compatible it should function correctly.
Midspan units are available from a variety
of sources, including many online retailers.

Microphone Input

The Model 208 provides a 3-pin female
XLR connector that allows a balanced
dynamic or phantom powered condenser
powered microphone to be connected.
The microphone can be a standalone
handheld (“stick”) type or can be part of a
broadcast-style headset. The Model 208’s
microphone input is directly compatible with
balanced dynamic or P48 phantom pow­ered microphones. A microphone should
be connected such that its associated XLR
connector has pin 1 as common, pin 2 as
signal high (+), and pin 3 as sign low (–). A
configuration setting allows the P48 mi­crophone power source to be enabled or

disabled as desired. Details on configuration
settings will be described later in this guide.

While the Model 208 provides an excellent
source of P48 phantom power, it’s possible
that an input that already provides micro­phone power will be connected to the unit’s
microphone output connector. This would
not create a problem since the circuitry that
connects audio from the Model 208’s micro­phone output connector to the Model 208’s
microphone input connector will pass this
microphone power through without interrup­tion. This situation could be relevant when
the Model 208’s microphone output connec­tor is interfaced with the microphone input
on a broadcast camera, audio console,
microphone mixer, or similar equipment.
Inputs on these devices would typically offer
phantom power which in some cases may
have been enabled.

Headphone Output

The Model 208 provides a 2-channel head­phone output by way of a 3-conductor
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 (“single­muff”) headset or broadcast-type single
earbud but in these cases some care must
be taken. If a 3-conductor ¼-inch plug is
used by a device it should be wired to the tip
and sleeve leads; the plug’s ring lead should
be left unconnected. But it’s also possible
that the monaural device will be terminated
on a 2-conductor (“tip and sleeve”) plug.
When the plug is inserted into the Model
208’s headphone jack the Model 208’s right

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headphone output channel will be shorted;
the ring lead will be directly connected to
the sleeve lead. This can lead to stress on
the right channel headphone output circuit­ry as well as extra current draw. To pre­vent 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 Configura­tion section later in this guide for details on
setting the headphone audio routing.

Microphone Output

A 3-pin male XLR connector provides a mi
crophone-level output that’s directly related
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 208’s
Dante main output channel is active the
microphone signal will also pass through
to the Model 208’s microphone output.
Whenever the Dante main output channel
is muted the microphone signal does not
pass through to the microphone output;
it’s is muted in an essentially click-free
manner. Refer to Appendix B for a block
diagram of the microphone input and
microphone output circuitry.

The microphone output can be connected
to balanced (differential) analog micro­phone-level inputs on a variety of devices.
This includes microphone input connec­tions on remote I/O interfaces associated
with a networked audio console. An ex­ample of such an interface would be the
Calrec® Hydra2®. The mic inputs on these
devices typically offer microphone power,
high-quality amplification, and conversion
to the digital domain. The output signals

of the interface’s pre-amp channels are
transported to the main electronics or con­sole surface using a fiber optic interface.
In this type of application the Model 208’s
Dante main output channel would not be
used or would only be used as a backup
path.

No preamplifier or other active circuitry im­pacts the path from the Model 208’s micro­phone input connector to the Model 208’s
microphone output connector. The signal
does pass through a 200 ohm resistor
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 connector. This will slightly raise
the theoretical noise floor of the micro­phone signal vis-a-vis a directly connected
microphone signal but shouldn’t impact
any real-world applications.

Remote Control Inputs

Provision has been made to allow exter­nal switches or contact closures to mimic
operation of the mic on/off and talkback
pushbutton switches. These in turn control
the status of the audio signal sent to the
main and talkback Dante output channels
as well as the microphone output connec­tor. A 3.5 mm 3-conductor jack is located
on the back panel and provides access to
the remote control inputs. The input circuit­ry is “active low,” with 3.4 k ohm resistors
connected to +3.3 volts DC to act as input
“pull ups.” (In addition a combination of
resistors and capacitors provide ESD pro­tection, minimizing the chance of damage
due to static discharge or other extraneous
signals.) A current flow of less than one
milliampere is required for a remote control
input to be recognized as active.

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Prepare the interconnecting cable and as­sociated 3.5 mm 3-conductor plug to reflect
that the tip lead is used to control the micro­phone on/off function, the ring lead is used
to control the talkback function, and the
sleeve lead is the connection to common.

Securing the Unit to a Surface

The Model 208 can be mounted to the top
or bottom (under) side of a flat surface
using the Studio Technologies MBK-02
bracket kit. The kit, purchased as an option,
contains two brackets, four 6-32 x 3/8-inch
screws, and four #6 lock washers. Refer to
Appendix A for details.

Begin by removing the two screws and as­sociated lock washers that secure the cover
to one side of the chassis. A 5/64-inch hex
driver is required to remove the screws.
Save the screws and the lock washers.
Using the 6-32 x 3/8-inch screws that are
included with the bracket kit, along with the
lock washers that were just removed, attach
one of the brackets to the applicable side of
the enclosure. If either or both lock washers
are misplaced use ones that are provided
in the MBK-02 kit.

The bracket can be mounted so that its
mounting flange faces down or faces up,
allowing the Model 208 to be attached to
the top side or the bottom (under) side
of a surface. Repeat the process on the
other side of the enclosure for the second
bracket. If possible, save the four standard
6-32 x ¼-inch screws and four lock washers
for future re-use if the brackets are ever
removed. Review the installation of the
brackets to ensure that they are both in
their desired orientation.

parameters be configured. These configu­ration settings will be stored in non-volatile
memory within the Model 208’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 support
Windows and OS X® operating systems.
The Model 208 uses the Ultimo 2-input/
2-output integrated circuit to implement
the Dante architecture.

The two Dante transmitter (Tx) channels
associated with the Model 208’s Dante
interface must be assigned to the desired
receiver channels. This achieves routing
the Model 208’s two output audio chan­nels 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 208’s transmitter chan­nels need to be routed to more than two
flows it’s possible that an intermediary
device with enhanced flow capability, such
as the Studio Technologies Model 5422
Dante Intercom Audio Engine, can be
used to “repeat” the signals.

The two Dante receiver (Rx) channels
associated with the Model 208’s audio
inputs also need to be routed to the de­sired Dante transmitter channels. These
two audio signals will be sent to the Model
208’s 2-channel headphone output.

Dante Configuration

For audio to pass to and from the Model
208 requires that several Dante-related

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The Model 208 supports audio sample
rates of 44.1, 48, 88.2, and 96 kHz with
no pull-up/pull-down values available.

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ANNOUNCER’S CONSOLE

In most cases it’s anticipated that the
default rate of 48 KHz will be appropriate.
While technically the Model 208 can serve
as a clock master for a Dante network
(as can all Dante-enabled devices) in
virtually all cases the unit will be config­ured to receive “sync” from another device.

The Model 208 has a default Dante device
name of ST-M208 along with a unique
suffix. The suffix identifies the specific
Model 208 that is being configured. The
suffix’s actual alpha and/or numeric char­acters relate to the MAC address of the
unit’s Ultimo integrated circuit. The two
Dante transmitter (Tx) channels have
default names of Main and Talkback. The
two Dante receiver (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 208 Configuration

The STcontroller software application is
used to configure the way in which the
Model 208 functions. No DIP switch set­tings or other local actions are used to
configure the unit. This makes it imperative
that STcontroller be available for conve­nient use in a personal computer that’s
connected to the related LAN.

The configurable functions include:

• P48 phantom power on/off status

• Microphone preamplifier gain

• Headphone output and sidetone modes,
gain range, and minimum level

• Mic on/off and talkback button modes

• System mode

Changes made using STcontoller will be
immediately reflected in the unit’s opera

­tion. No Model 208 “reboot” is required.
Each time a change is made the mic on/off
and talkback buttons on the front panel will
momentarily flash orange to indicate that
a command from STcontroller has been
received.

Installing STcontroller

STcontroller is available free of charge
on the Studio Technologies website (www.
studio-tech.com/stcontroller) and is com­patible with personal computers running
Windows operating systems that are
version 7 and later. STcontroller versions

1.02.00 and later will fully support the Mod­el 208. If required, download and install
STcontroller onto a designated personal
computer. This personal computer must be
on the same local area network (LAN) and
subnet as the Model 208 unit or units that
are to be configured. Immediately after
starting STcontroller the application will
locate the devices that it can control. The
Model 208 unit or units will appear in the
device list. Use the identify command to
allow easy recognition of a specific Model
208 unit. Double-clicking on a device name
will cause the associated configuration
menu to appear. Review the current con­figuration and make changes as required.

P48 Phantom Power

STcontroller allows selection of the on/
off status of the microphone input’s P48
phantom power source. The on/off sta

­tus is displayed by way of an LED, red in
color, located on the back panel adjacent
to the microphone input connector. Select
the status of the P48 source to meet the
needs of the connected microphone. No
problem will occur if an external source of
P12 or P48 phantom power is present on

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the connection made to the microphone
output connector. In this case simply turn
off the Model 208’s P48 phantom power
source. The external source of microphone
power will “pass thru” from the microphone
output connector to the microphone input
connector.

Microphone Preamp Gain

The gain of the Model 208’s microphone
preamplifier can be selected from among
four choices: 35, 43, 52, and 59 dB. The
compressor active LED, orange in color
and visible on the back of the Model 208’s
enclosure adjacent to the microphone
input connector, can act as a guide when
setting the preamp gain. When a voice
signal at a normal level is present on the
microphone input the compressor 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
the 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 otherwise
indicated, 43 dB is typically a good initial
choice.

Headphone Output Mode

STcontroller allows selection from among
four headphone output modes. Each mode
is distinct and careful selection will help
optimize the Model 208’s operation for a
range of applications.

Level/Level

The level/level mode is provided for on­air applications where two independent
audio sources need to be routed to sepa­rate headphone output channels. Dante
audio input channel 1 will be routed to the
left headphone output channel and the

front-panel left phones potentiometer will
adjust its level. Dante audio input chan­nel 2 will be routed to the right headphone
output channel and the right phones
potentiometer will adjust its level.

Level/Balance

The level/balance mode is provided for
stereo applications such as live music
events that are distributed via streaming
or broadcast radio. In these applications
it’s typical to want the user to have a single
control to simultaneously adjust the level of
both channels while a separate control is
used to adjust the left/right level balance.

When set for the level/balance mode
Dante input channel 1 will be routed to
the left headphone output channel and
Dante input channel 2 will be routed to the
right headphone output channel. The left
phones potentiometer will adjust the over­all level of 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 combined (mixed
together or “summed”) and routed to
both the left and right channels of the
headphone output. The left phones poten­tiometer adjusts the level of Dante audio
input 1 and the right phones potentiometer
adjusts the level of Dante audio input 2.

Single-Channel Monaural

The single-channel monaural mode is
specifically provided for applications where
a 2-conductor ¼-inch plug is being used

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with the connected headphones, headset,
or a broadcast-style earpiece. In this mode
Dante audio inputs 1 and 2 are combined
to monaural and routed to only the left
channel of the headphone output; no audio
signal is routed to the right channel of the
headphone output. The left phones poten­tiometer adjusts the level of Dante audio
input 1 and the right phones potentiometer
adjusts the level of Dante audio input 2.

Headphone Gain Range

The overall level of the headphone output
can be configured as desired for specific
applications. The default setting, low, is
designed so that users with typical audio
input sources will be inclined to set the
rotary controls at approximately 50% of
rotation. This would be appropriate for
most applications. The high setting would
be applicable in cases where an extreme
headphone output level is required or the
audio input sources are providing a level
that is lower than typical. Using the high
setting in the former application is not
recommended as hearing damage could
result from exposure to high signal levels.

Headphone Minimum Level

A setting in STcontroller is used to con

­figure the headphone output’s minimum
level. In the –40 dB setting the minimum
headphone output level is approximately
40 dB below its maximum; the headphone
output will never fully mute. This ensures
that any audio signal present on either of
the Dante audio input channels will always
be present on the headphone output. In
most on-air broadcast applications this
is the appropriate setting, ensuring that
a minimum amount of signal is always
present. When full mute is selected mov­ing either level control to its fully counter­clockwise position will cause its associated

headphone output channel (or channels)
to fully mute. If a rotary level control is set
to serve as a balance control, moving it
to either its fully counterclockwise or fully
clockwise position will cause the associ­ated signal to fully mute. Selecting the full
mute mode may be appropriate for ap­plications where minimizing the chance of
audio “leakage” is important. This could
occur when the connected headset or
headphones are at times placed on a
desk or tabletop.

Note that the rotary level control, located
on the far right side of the front panel,
controls the sidetone level and the setting
of the headphone minimum level will not
impact it. Whenever the sidetone control
is in its fully counterclockwise position it
will always cause the sidetone audio
signal being sent to the headphone
output channels to be fully muted.

Sidetone Mode

STcontroller allows the Model 208’s side­tone function to be configured as desired.
Sidetone is audio from the microphone
input that is sent to the headphone output
channels. This can be important, allowing
the user to “hear” themselves for perfor­mance confirmation and comfort. Making
a specific selection from among the four
available modes will depend on the needs
of the application. If a “full mix” is being
provided to the Model 208’s audio inputs
then locally provided sidetone won’t be
needed. The user will hear themselves
by way of the audio signals being routed
to the Dante audio input channels. But
if a “mix-minus” is being supplied to the
Model 208 then having one of the side­tone modes enabled can be an important
means of establishing user confidence.

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Four sidetone modes are available:

• Off: In this mode the sidetone function
is not active.

• Mic On/Off Button: In this mode the sid­etone function will be active whenever
the audio signal associated with the mic
input is present on the Dante main out­put channel and the microphone output
connector.

• Talkback Button: In this mode the side­tone function will be active whenever the
talkback function is active and the audio
signal is present on the Dante talkback
output channel.

• Mic On/Off and Talkback Buttons: In
this mode the sidetone function will be
active whenever the audio signal as­sociated with the mic input is present on
the Dante main output channel and the
microphone output connector. The side­tone function will also be active when­ever the talkback function is active.

Mic On/Off Button

STcontroller allows the configuration of the
mic on/off button to be selected. There are
five mode choices available:

• Push to Mute: If this mode is selected
the mic on/off function will normally be
active and its green LED lit. The audio
signal associated with the microphone
input will be routed to both the Dante
main output channel and the microphone
output connector. Whenever the button
is pressed the audio signal will mute on
both the Dante main output channel and
the microphone output connector; the
LED on the button will no longer be lit.

• Push to Talk: If this mode is selected the
mic on/off function will normally be inac­tive and the button LED not lit. The audio

signal associated with the microphone
input will not be routed to the Dante
main output channel and the microphone
output connector will be muted. When­ever the mic on/off button is pressed the
audio signal will become active on the
Dante main output channel and the mi­crophone output connector. In addition,
the button LED will light.

• Latching: If this mode is selected the
mic on/off function will alternate between
its on (active) and off (inactive) states
whenever the button is pressed. Upon
power up the function will be in its off
state and the LED on the button will not
be lit.

• Push to Talk/Tap to Latch: This mode is
a combination of the Push to Talk and
Latching modes. It’s similar to the way
talk pushbutton switches function on
user stations associated with broadcast
or production intercom systems. If the
button is pressed and held the mic on/off
button function will be on. It will stay
active until the button is released. If the
mic on/off button is momentarily “tapped”
the mic on/off status will change, either
from off-to-on or from on-to-off. Upon
Model 208 power up the mic on/off but­ton will be in its off state and its LED will
not be lit.

• Push to Mute/Tap to Latch: This mode
is a combination of the Push to Mute
and Latching modes. Whenever the mic
on/off button is momentarily “tapped” the
mic on/off button’s status will change,
either from active-to-inactive or inac­tive-to-active. When the mic on/off but­ton function is active its green LED will
be lit. The audio signal associated with
the microphone input will be routed to
both the Dante main output channel and

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the microphone output connector. When
ever the mic on/off button is pressed and
held the audio signal will mute on both
the Dante main output channel and the
microphone output connector and the but­ton’s LED will no longer light. It will stay
in this condition until the mic on/off button
is released. Upon Model 208 power up
the mic on/off button will be in its inactive
state and its LED will not be lit.

Talkback Button Mode

The manner in which the talkback button
functions can be configured. There are
three mode choices available:

• Push to Talk: If this mode is selected the
talkback function will normally be inactive
and the button LED not lit. Whenever the
button is pressed the talkback function
will become active and the button LED
will light.

• Latching: If this mode is selected the talk­back function will alternate between its on
(active) and off (inactive) states whenever
the button is pressed. Upon power up the
function will be in its off state and the but­ton LED will not be lit.

• Push to Talk/Tap to Latch: This mode is
a combination of the Push to Talk and
Latching modes. It’s similar to the way
talk pushbutton switches function on user
stations associated with broadcast or pro­duction intercom systems. If the talkback
button is pressed and held the talkback
function will be on (active). It will stay
active until the button is released. If the
talkback button is momentarily “tapped”
the status of the talkback function will
change, either off-to-on or on-to-off. Upon
Model 208 power up the talkback button
will be in its off state and its LED will not
be lit.

-

System Mode

The system mode configures the overall
manner in which the Model 208 operates.
Specifically, it determines how the Dante
main output channel and the microphone
output connector operate vis-à-vis the
talkback function. The system mode can
also impact one facet of the headphone
output’s function. There are three system
modes available. Understanding how each
specifically impacts Model 208 operation
will help to ensure that the desired opera­tion is obtained and that maximum usabil­ity will occur.

On-Air

When selected to the on-air mode, audio
on the Dante main output channel and the
microphone output connector will always
mute whenever the talkback function is ac­tive. The on-air mode should be selected
for all on-air broadcast applications when
it’s imperative that the “on-air” audio sig­nal be muted whenever on-air talent uses
the talkback function to communicate with
production personnel.

Production

When the system mode is set for produc­tion, the audio signals on the Dante main
output channel and microphone output
connector are never muted in response to
talkback function activity. The mic off/off
function operates independently of the
talkback function. This mode allows the
Dante main output channel to be used, for
example, as an additional talkback output.
In this way the Dante main and talkback
output channels can be used separately,
with neither impacting the other. This also
allows both the mic on/off and talkback
pushbuttons to be used simultaneously.
When selected for the correct application,

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the production mode can prove to be very
useful. But it’s not appropriate for on-air
use!

Production with Dim

This mode is identical to the production
mode with the exception that the head­phone output reduces in level (“dims”)
whenever the mic on/off or talkback func­tions are active. This mode was specifi­cally provided to minimize the chance that
acoustical feedback will occur in applica­tions where the headphone output is con­nected to the inputs on amplified speakers.
(Or inputs on an amplifier associated with
loudspeakers.) In this mode the level of
the headphone output channels is reduced
by 18 dB whenever the mic on/off or talk­back functions are active. This mode is not
appropriate when headphones are going
to be connected to the Model 208!

Operation

At this point all connections and configura­tion steps should have been completed
and everything should be ready for Model
208 operation to 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 connection to the microphone
output should have been made. Special
applications may utilize either or both of
the remote control inputs.

The Model 208 should have been placed
in the desired physical location. This may
involve securing the unit to a fixed loca­tion using the optional mounting brackets.
Using the Studio Technologies STcontroller
software application the unit’s configura­tion should have been set to meet the
needs of the specific application. The
Model 208’s Dante configuration settings
should have been selected using the
Dante Controller software application. 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.

Initial Operation

The Model 208 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 back
panel below the RJ45 jack, will begin to
light as network and Dante connections
are established. The COMP LED, adjacent
to the microphone input connector, may or
may not flash momentarily. The P48 LED,
also located adjacent to the microphone
input connector, will flash once to indicate
that it is functioning. The green and orange
LEDs within the mic on/off and talkback
pushbutton switch will light in a short test
sequence to indicate that the application
firmware (embedded software) has started.
Once that sequence has completed and
the Dante connection has been estab­lished full operation will begin. The vari­ous LEDs will then become operational,
displaying the status of their designated
functions.

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How to Identify a Specific
Model 208

Functions within the Dante Controller and
STcontroller software applications allow
a specific Model 208 unit to be identified.
Each application provides an “eyeball” icon
that when clicked will activate the identify
function. When identify is selected it will
send a command to a specific Model 208
unit. On that unit the orange LEDs as­sociated with the mic on/off and talkback
pushbutton switches will flash on and off
approximately eight times. (The on/off
status of the buttons will not change.) In
addition, the SYS and SYNC status LEDs,
located directly below the etherCON RJ45
connector on the back panel, will slowly
flash green. After a few seconds the LED
identification pattern will cease and normal
Model 208 button LED and Dante status
LED operation will resume.

Ethernet and Dante Status
LEDs

Three status LEDs are located below the
etherCON RJ45 connector on the Model
208’s back panel. The LINK ACT LED will
light green whenever an active connection
to a 100 Mb/s Ethernet network has been
established. It will flash in response to
Ethernet data packet activity. The SYS and
SYNC LEDs display the operating status
of the Dante interface and its associated
network activity. The SYS LED will light
red upon Model 208 power up to indicate
that the Dante interface is not 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 208 is not synchronized
with a Dante network. It will light solid
green when the Model 208 is synchronized
with a Dante network and an external

clock source (timing reference) is being
received. It will slowly flash green when
this specific Model 208 is part of a Dante
network and is serving as the clock mas­ter. It’s possible that up to 30 seconds may
be required for the SYNC LED to reach its
final state.

P48 Status LED

A red LED indicator is located on the back
panel adjacent to the microphone input
connector. It is labeled P48 and will light
whenever the P48 phantom power source
is active and providing power to the micro­phone input.

Compressor Active LED and
Mic Preamp Gain

An orange LED indicator is located on the
back panel, also adjacent to the micro­phone input connector. It is labeled COMP
and displays the status of the microphone
audio compressor function. This function
controls the dynamic range of the audio
signal that can be present on the Dante
output (transmitter) channels and side­tone audio sent to the headphone output
versus the signal present on the micro­phone input. The compressor LED will
light whenever the input level from the
microphone, along with the configured
mic preamp gain, is such that the dynamic
range of the signal is being actively con­trolled. It’s perfectly acceptable for this
LED to light intermittently whenever a user
is talking at a normal voice level into an
associated microphone. 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. Conversely, if the COMP LED
almost never lights when normal talking is
taking place, it’s possible that changing the

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gain to a higher value would be beneficial.
Note that due to the design of the circuitry
the compressor active LED will function
whether or not the main or talkback func­tions are active. Also, the compressor
function does not impact the microphone
output connector.

Microphone On/Off and
Talkback Buttons

Two pushbutton switches are used to
select how the microphone signal is routed
to the two Dante output channels and the
microphone output connector. The button
labeled MIC ON/OFF controls if the audio
signal associated with the microphone
input will be present on the Dante main
output channel and the microphone output
connector on the back panel of the Model

208. How the button functions will depend
on the configuration choice that has been
made using STcontroller. When the mic
on/off button’s green LED is lit audio will
be present on both the Dante main output
channel and the microphone output con­nector. When the mic on/off button’s LED
is not lit audio will not be present on the
Dante main output channel and the audio
signal associated with the microphone
output connector will be muted.

The talkback function allows the audio as­sociated with the microphone input to be
routed to the Dante talkback output chan­nel. When the talkback button’s green LED
is lit the talkback function will be active.
When the talkback button’s LED is not lit
the talkback function is not active. How the
talkback button will specifically function
and whether it impacts the microphone
on/off function will depend on the configu­ration of the Model 208.

Mic On/Off Button Modes

There are five ways that the mic on/off
pushbutton can function. A specific Model
208 unit’s operating mode will depend on
its selected configuration.

• Push to Mute: If this mode is selected the
audio signal associated with the micro­phone input will normally be active on
the Dante main output channel and the
microphone output connector. The audio
signal will mute whenever the mic on/off
pushbutton is pressed and held.

• Push to Talk: If this mode is selected the
audio signal associated with the Dante
main output channel and the microphone
output connector will be normally muted.
The audio signal will become active
whenever the mic on/off pushbutton is
pressed and held.

• Latching: If this mode is selected the
audio signal associated with the Dante
main output channel and the microphone
output connector will alternate between
the active and muted states whenever the
mic on/off pushbutton is pressed. Upon
Model 208 power up the audio signal will
be in its muted state.

• Push to Talk/Tap to Latch: This mode is
a combination of the Push to Talk and
Latching actions. It’s similar to the way in
which talk pushbuttons function on user
stations associated with broadcast or
production intercom systems. If the mic
on/off pushbutton is pressed and held the
audio signal associated with the Dante
main output channel and the microphone
output connector will become active and
remain active until the pushbutton is
released. If the mic on/off pushbutton is
momentarily “tapped” the audio signal will
change state. Upon Model 208 power up
the audio signal will be in its muted state.

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• Push to Mute/Tap to Latch: This mode
is a combination of the Push to Mute
and Latching modes. Whenever the mic
on/off button is momentarily “tapped”
its status will alternate between active
and muted. When the mic on/off button’s
function is active and the mic on/off but­ton is pressed and held the audio signal
will mute on both the Dante main output
channel and the microphone output con­nector. It will stay in this condition until
the mic on/off button is released. Upon
Model 208 power up the mic on/off but­ton will be in its muted state.

Talkback Button Modes

Depending on the selected configuration,
the talkback pushbutton will function in
one of three possible modes:

• Push to Talk: If this mode is selected the
audio signal associated with the Dante
talkback output channel is normally
muted. The audio signal will become
active whenever the talkback pushbutton
is pressed and held.

• Latching: If this mode is selected the
audio signal associated with the Dante
talkback output channel will alternate
between its active and muted states
whenever the talkback pushbutton is
pressed. Upon Model 208 power up the
Dante talkback output channel will be
in its muted state.

• Push to Talk/Tap to Latch: This mode
is a combination of the Push to Talk and
Latching actions. If the talkback push­button is pressed and held the audio
signal associated with the Dante talkback
output channel will become active until
the pushbutton is released. If the talk­back pushbutton is momentarily “tapped”
the audio signal on the Dante talkback

output channel will change state. Upon
Model 208 power up the audio signal on
the Dante talkback output channel will be
in its muted state.

Remote Control Inputs

The Model 208 allows two external con­tacts to be connected to the remote control
inputs. Whether or not they are utilized
will depend on the selected application. If
either or both are utilized they will provide
an action identical to that caused by press­ing or tapping the mic on/off and talkback
pushbutton switches. How they specifically
function will depend on how the buttons are
configured. For example, if the mic on/off
button is configured for latching mode the
mic on/off remote control input will provide
the same action as would utilizing the
mechanical pushbutton switch.

System Mode

The system mode configuration is used to
select the overall operating mode of the
Model 208. Specifically, the system mode
determines how the mic on/off function
operates vis-à-vis the talkback function as
well as if the level of the headphone output
is impacted by pushbutton activity. Un­derstanding how the three system modes
impact overall system operation will ensure
correct operation and maximum usability.

• On-Air: When the system mode has been
selected to on-air the mic on/off function
will be forced off whenever the talkback
function is active. The on-air mode will
be appropriate for all on-air broadcast
applications where it’s imperative that
the audio signal on the Dante main output
channel and microphone output connec­tor be muted whenever on-air talent uses
the talkback function to communicate with
production personnel.

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• Production: When set for the production
mode the status of the mic on/off function
will never be impacted by the status of the
talkback function. This mode allows the
Dante main output channel to be used, for
example, as an additional talkback output.
In this way the Dante main and talkback
output channels can be used indepen­dently, with activation of either never
impacting the other. This also allows both
pushbuttons to be used simultaneously.
When selected for the correct application,
the production mode can prove to be very
useful. But it’s not appropriate for on-air
use!

• Production with Dim: This mode functions
exactly as the production mode does with
one addition. The level of the headphone
output is dimmed (reduced in level or at­tenuated) by 18 dB whenever the main
on/off or talkback functions are active.
In this way the headphone output can
be connected to amplified loudspeakers
without the risk of acoustical feedback.
The selection of this mode will be clearly
evident as speakers (or a connected set
of headphones) will automatically reduce
in level whenever the mic on/off or talk­back functions is active.

gain range configuration allows the overall
output level to be selected. The minimum
level configuration will determine what
occurs when the pots are in their fully
counterclockwise position.

Users should find the headphone 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 each pot is
recognized by the Model 208’s processor
which then adjusts the appropriate signal
level within the digital domain. The pots
are “push-in/push-out” type which allow
their associated knobs to be in their “out”
position when adjustment is desired and
their “in” position when protection from an
unwanted change is beneficial.

Output Mode

Four output modes allow the overall head­phone output performance to be config­ured:

• Level/Level: In this mode the left phones
pot will control the level of Dante input 1
as it is being sent to the left channel of
the headphone output. The right phones
pot will control the level of Dante input 2
as it is sent to the right output.

Headphone Output

Three rotary potentiometers (pots),
located on the Model 208’s front panel,
allow adjustment of the level of the two
Dante audio input channels and the sid­etone (local microphone) audio signal as
they are sent to the 2-channel headphone
output. How the pots function will depend
on the selected configuration. Four output
modes are available and determine the
overall performance. The sidetone mode
determines how the sidetone function, and
its associated level control, will operate. The

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• Level/Balance: In the level/balance
mode Dante input 1 will be sent to the
left channel headphone output while
Dante input 2 will be sent to the right
channel of the headphone output. 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.

• Dual-Channel Monaural: When this
mode is selected the left phones pot
will adjust the level of Dante input 1

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as it is routed 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 headphone outputs.

• Single-Channel Monaural: When the
Model 208 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 to the left
headphone output channel; no audio
is sent to the right headphone output
channel.

Sidetone

The Model 208 includes a sidetone
function that allows microphone audio
(electrically following the microphone
preamplifier) to be sent to the headphone
output. The sidetone function can be
configured to operate from among four
choices.

• Off: When configured to the off mode no
microphone audio will be sent to either
of the headphone output channels. In
this mode the sidetone function is fully
disabled.

• Mic On/Off Button: When configured for
this mode the sidetone function will be
active whenever microphone audio is
actively being sent to the Dante main
output channel and the microphone
output connector. When the mic on/off
function is not active no sidetone audio
will be sent to the phones output.

• Talkback Button: When the mode is
configured for talkback button the side­tone function will be active whenever
the talkback function is active.

• Mic & Talkback Buttons: When config­ured for this mode the sidetone function
will be active whenever either the mic
on/off or talkback functions are active.

Sidetone audio quality will be excellent and
can provide a Model 208 user with a confi­dence signal whenever their microphone
is “active” but their talent cue signal
doesn’t return their own voice audio. This
can be important in cases where “mix-mi­nus” cue signals are being provided to the
user by way of the Dante audio inputs.

Whether sidetone audio will be sent to the
left and right headphone output channels
or only the left headphone output chan­nel will depend on the configuration of the
headphone output mode. As expected,
should the headphone output mode be
configured for level/level, level/balance,
or dual-channel monaural, sidetone audio
will be sent to both the left and right head­phone output channels. When configured
for single-channel monaural, sidetone au­dio will be sent only to the left headphone
output channel.

Gain Range

A configuration setting allows the over

­all headphone output gain range to be
selected. The low setting is appropriate
for most where users who need to listen
to the headphone output at a moderate
level. The high setting can be useful when
monitoring at higher levels is warranted by
an application. Alternately, the high set­ting can be useful for applications where
the audio source is very low in level and
the extra gain can bring the signal up to
a useful listening condition. For example,
in golf broadcast applications on-air talent
frequently has to speak at a very low level
so as to not interfere with participants.

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Minimum Level

How the headphone output channels
function when a pot is in its fully counter­clockwise position will depend on the con­figuration of the minimum level function.
Also, when the headphone output mode
is selected for the level/balance mode the
minimum level configuration setting will
determine what happens when the balance
pot is set to either its fully counterclockwise
or fully clockwise positions. Two selections
are available:

• Full Mute: When the minimum level
configuration is set for full mute turning a
pot to its fully counterclockwise position
will cause the associated audio signal to
be fully muted. So, as an example, in the
level/level mode turning the left head­phone output level control fully counter­clockwise will cause the audio associated
with Dante input channel 1 to mute and
not be sent to the left headphone output.
And in the case where the level/balance
mode has been selected turning the
balance control to either end of its travel
will cause the applicable channel to fully
mute.

• –40 dB: When configured for this mode
the maximum attenuation of an audio
signal when sent to a headphone output
channel is 40 dB below its maximum.
This mode is provided for applications
where important cue signals never
should be fully muted. In live television or
streaming events this can be particularly
useful. This can ensure that producer or
director cues will always be heard, even
if at a greatly reduced level. It can be
important to alert users that this configu­ration has been selected. Otherwise they
can mistake the low level of audio pres­ent on the headphone output to be audio
“leakage” or “crosstalk” situation.

Technical Notes

IP Address Assignment

By default the Model 208’s Ethernet inter­face will attempt to automatically obtain an
IP address and associated settings using
DHCP (Dynamic Host Configuration Proto­col). If a DHCP server is not detected
an IP address will automatically be as­signed using the link-local protocol. This
protocol 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
interconnected using an RJ45 patch cord
will, in many cases, correctly acquire IP
addresses and be able to communicate
with each other.

An exception does arise when trying to
directly interconnect two Dante-enabled
devices that use Ultimo integrated circuits
to implement Dante. The Model 208 uses
Ultimo 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 Ultimo­based devices. The technical reason 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
application the Model 208’s IP address
and related network parameters can be
set for a fixed (static) configuration. While

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this is a more involved process than simply
letting 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 knowledge
of a Model 208’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 specific Mod­el 208’s IP address is “lost,” the Address
Resolution 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 information that
includes MAC addresses and correspond­ing IP addresses. The simplest means of
identifying an unknown IP address is to cre­ate a “mini” LAN with a small PoE-enabled
Ethernet switch connecting a personal
computer to the Model 208. Then by using
the appropriate ARP command the required
“clues” can be obtained.

Optimizing Network
Performance

For best Dante audio-over-Ethernet per­formance a network that supports VoIP
QoS (voice-over-internet-protocol quality of
service) capability is recommended. This
can typically be implemented on virtually all
contemporary 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 optimiz­ing networks for Dante applications.

Application Firmware Version
Display

There are two ways in which the version
number of the Model 208’s application
firmware (embedded software) can be
identified. One requires only the Model
208 unit and involves a button press se­quence performed upon power up. The
other method utilizes the Model 208 and
the STcontroller software application. Ei­ther method may prove to be useful when
working with factory personnel on applica­tion support and troubleshooting.

As part of the Model 208’s power-up
sequence the unit’s application firmware
can be directly displayed. Before con­necting the PoE-enabled Ethernet cable,
press and hold the talkback button. Then
connect the Ethernet cable. Upon applica­tion of PoE power the Model 208 will not
go through its normal power-up sequence
but instead will display the firmware ver­sion. The LED associated with the mic
on/off button will “flash” green in color to
display the major version number and then
“flash” orange to display the minor version
number. Then the LED will remain off until
the talkback button is released. Once the
talkback button is released normal opera­tion will then take place. As an example of
what would be a typical firmware display,
if the mic on/off button’s LED “flashes”
green once followed by the LED “flashing”
orange once it would indicate that applica­tion firmware version 1.1 is present in the
Model 208.

A selection in the STcontroller software
application allows the Model 208’s ap­plication firmware version to be identified.
Connect the Model 208 unit to the network
and let it connect and start to function.
Then, after starting STcontroller, review

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the list of identified devices and select the
specific Model 208 from which you want to
determine its application firmware version.
Then select Version under the Device tab.
A page will then display that will provide
lots of useful information. This includes the
application firmware version and well as
details on the Dante interface firmware.

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.

Application Firmware Update
Procedure

It’s possible that updated versions of the
application firmware (embedded software)
that is utilized by the Model 208’s proces­sor (microcontroller or MCU) integrated
circuit will be released to add features or
correct issues. Refer to the Studio Tech­nologies website for the latest application
firmware file. The unit has the ability to
load a revised file into the MCU’s non­volatile memory by way of a USB inter­face. The Model 208 implements a USB
host function that directly supports connec­tion of a USB flash drive. The Model 208’s
MCU updates its firmware using a file
named m208.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
format. Save the new firmware file in the
root directory with a name of m208.bin.
Studio Technologies will supply the ap­plication firmware file inside a .zip archive
file. While the firmware file inside of the
zip file will adhere to the naming conven­tion required by the Model 208, the name
of the zip file itself will include the file’s
version number. For example, a file named
m208v1r1MCU.zip would indicate that
version 1.1 of the application firmware
(m208.bin) is contained within this zip file.

To install an application firmware file follow
these steps:

1. Disconnect power from the Model 208.
This will entail removing the Ethernet
connection that is providing PoE
power.

2. Remove the cover from the Model 208.
Begin by removing the four hex head
machine screws, two per side, using a
5/64-inch hex driver. Be certain to save
the screws and associated lock wash­ers so that re-assembly will be fast and
painless. Then carefully slide the cover
forward, lifting it off once it has cleared
away from the level controls and
buttons.

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 the connector.

4. Apply power to the Model 208 by
connecting to a Power-over-Ethernet
(PoE) Ethernet source.

5. After a few seconds the Model 208 will
run a “boot loader” program that will
automatically load the new application
firmware file (m208.bin). This loading
process will take only a few seconds.
During this time period the mic on/off
button LED will flash slowly in alter­nating colors. Once the entire loading

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process is over, taking approximately
10 seconds, the Model 208 will restart
using the newly-loaded application firm­ware.

6. At this time the Model 208 is function­ing with the newly-loaded application
firmware and the USB flash drive can
be removed. But to be conservative, re­move PoE power first and then remove
the USB flash drive.

7. Confirm that the desired firmware
version has been correctly loaded. This
can be done by pressing and holding
the talkback button, applying power to
the Model 208, and then “reading” the
application firmware version number
by observing the mic on/off button’s
LED. Alternately, the STcontroller ap­plication can be used to identify the
application firmware version number.
Whatever method you use, ensure that
the desired version is present.

Note that if a connected USB flash drive
doesn’t have the correct file (m208.bin)
in its root folder no harm will occur if power
is applied to the Model 208. Upon power
up the mic on/off button’s LED will flash
on and off rapidly for a few seconds to
indicate this condition and then normal
operation using the unit’s existing applica­tion firmware will begin.

application can also be used to identify the
firmware version. (Use the Version selec­tion under the Device tab.) The Dante
firmware can be updated by way of the
Model 208’s Ethernet connection. The lat­est Dante firmware file is available on the
Studio Technologies website. The Dante
Firmware Update Manager (FUM) appli­cation is used to install the firmware. This
program is also available for download on
the Studio Technologies website. It’s an­ticipated that a more automated method of
updating Dante firmware will become avail­able. It this comes to fruition then it might
offer a much simplified method of keeping
the firmware current.

Restoring Factory Defaults

A command in the STcontroller software
application allows the Model 208’s defaults
to be reset to the factory values. From
STcontroller select the Model 208 for which
you want to restore its defaults. Select the
Device tab and then the Defaults tab.
Select the Factory Defaults feature. Then
click on the OK box. The values shown
on the screen should reflect the default
values. They are:

Microphone P48 Phantom Power: Off

Microphone Pre-Amplifier Gain: 35 dB

Headphone Output Mode: Level/Level

Ultimo Firmware Update

As previously discussed in this guide, the
Model 208 implements Dante connectivity
using the 2-input/2-output Ultimo integrat­ed circuit from Audinate. The Dante Con­troller software application can be used
to determine the version of the firmware
(embedded software) that resides in the
Ultimo “chip.” The STcontroller software

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Sidetone Mode: Mic & Talkback But-

tons

Headphone Gain Range: Low

Headphone Minimum Level: –40 dB

Mic On/Off Button: Push to Mute

Talkback Button: Push to Talk

System Mode: On-Air

MODEL 208

ANNOUNCER’S CONSOLE

Specifications

Power Source:
Power-over-Ethernet (PoE): class 1 (very low

power, ≤3.84 watts)

Network Audio Technology:
Type:

Dante audio-over-Ethernet

Bit Depth: up to 24
Sample Rate: 44.1, 48, 88.2, and 96 kHz
Number of Transmitter (Output) Channels:
Number of Receiver (Input) Channels: 2
Dante Audio Flows: 4; 2 transmitter, 2 receiver
AES67-2013 Support: yes
Dante Domain Manager (DDM) Support: yes

Network Interface:
Type:

100BASE-TX, twisted-pair Ethernet, Power-

over-Ethernet (PoE) supported
Data Rate: 100 Mb/s (10 Mb/s and 1000 Mb/s

“GigE” Ethernet not supported)

Microphone Input:
Compatibility: dynamic or phantom-powered

microphones

Type:

balanced, capacitive coupled

Impedance: 2 k ohms, nominal
Gain: 35, 43, 52, 59 dB, selectable
Frequency Response: 25 Hz to 20 kHz, –3 dB
Distortion (THD+N): <0.022%, measured at 35 dB

of gain

Dynamic Range: 96 dB, A-weighted
Phantom Power: P48 per IEC 61938 standard,

on/off selectable with status LED

Compressor:
Application: applies to Dante main and talkback

transmitter (output) channels

Threshold: 1 dB above nominal level (–19 dBFS)
Slope: 2:1
Status LED: compressor active

Microphone Output:
Type:

passive, via two 200 ohm resistors from
microphone input (will pass phantom power in
either direction)

Muting: solid-state relay contacts, 60 dB
attenuation @ 1 kHz

2

Headphone Output:
Type:

dual-channel

Compatibility: intended for connection to stereo
(dual-channel) or monaural (single-channel) head­phones, headsets, or earpieces with nominal
impedance of 50 ohms or greater

Maximum Output Voltage: 3.8 Vrms, 1 kHz,
150 ohm load

Frequency Response: 20 Hz to 20 kHz, –2 dB
Distortion (THD+N): <0.002%
Dynamic Range: >100 dB

Remote Control Inputs:
Functions: controls mic on/off and talkback

functions
Type: active low, 1 mA maximum, inputs pull up

to 3.3 volts DC

Connectors:
Microphone Input: 3-pin female XLR
Microphone Output: 3-pin male XLR
Headphone Output: 3-conductor ¼-inch jack
Remote Control Inputs: 3-conductor 3.5 mm jack
Ethernet: Neutrik etherCON RJ45
USB: type A receptacle (located inside Model 208’s

enclosure and used only for updating firmware)

Configuration: requires Studio Technologies
STcontroller personal computer application,
version 1.02.00 and later (STcontroller compatibl
with Windows® version 7 and later)

Dimensions (Overall):

4.5 inches wide (11.4 cm)

1.6 inches high (4.0 cm)

4.8 inches deep (12.6 cm)

Mounting: intended for tabletop applications, top
or bottom mounting with optional mounting bracket
kit (Order Code: MBK-02)

Weight:

Specifications and information contained in this
User Guide subject to change without notice.

0.75 pounds (0.34 kg)

e

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Appendix A: Views of Model 208 with Optional

4.5"

5.09"

4.79"

3.6"

2.5"

0.17"
(4x)

5.49"

Front

Overall Height with Brackets Installed = 1.63"

MBK-02 Mounting Brackets Installed

MBK-02 Mounting Brackets shown in

Bottom-Mount (left) and Top-Mount (right) Positions

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MODEL 208

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Appendix B: Model 208 Block Diagram

MODEL 208 ANNOUNCER’S CONSOLE
MICROPHONE INPUT AND OUTPUT
SIMPLIFIED BLOCK DIAGRAM

MICROPHONE

PREAMPLIFIER

35, 43, 52, OR 59 dB

TO

ANALOG-

TO-DIGITAL

CONVERTER

DIGITAL CONTROL

2

3

1

MICROPHONE

INPUT

(XLR-3F)

MICROPHONE

OUTPUT

(XLR-3M)

COMPRESSOR

PASSIVE
MUTING

NETWORK*

(400 OHM

INSERTION

IMPEDANCE)

ISOLATION

AND

PROTECTION

ACTIVE

2

3

1

DIGITAL CONTROL

* ALLOWS P12 AND P48 PHANTOM POWER TO PASS

FROM MICROPHONE OUTPUT TO MICROPHONE INPUT

.
INTERNAL P48 PAHANTOM SUPPLY IS RECOMMENDED
FOR OPTIMAL PEROFRMANCE.

LOW-NOISE
P48 POWER

SOURCE

DIGITAL CONTROL

6K85 (x2)

The following block diagram shows a simplified version of the Model 208’s microphone
input and microphone output circuitry.

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