User Guide
Issue 5, September 2012
This User Guide is applicable for serial numbers:
M210-01151 to M210-01250
Copyright © 2012 by Studio Technologies, Inc., all rights reserved
www.studio-tech.com
50311-0912, Issue 5
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Table of Contents
Introduction ................................................................... 5
System Features ........................................................... 5
Installation and Setup ................................................... 9
Configuration ................................................................ 14
Operation ...................................................................... 22
Technical Notes ............................................................. 25
Specifications ................................................................ 35
Appendix A .................................................................... 36
Block Diagram
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Issue 5, September 2012 Model 210 User Guide
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Introduction
What This User Guide Covers
This User Guide is designed to assist you
when installing, configuring, and using
Model 210 Announcer’s Consoles with
serial numbers 01151 to 01250. Additional
background technical information is also
provided. A product block diagram is
included at the end of this guide.
System Overview
The Model 210 Announcer’s Console is
designed to serve as the audio control
center for announcers, commentators,
and production talent. The tabletop unit is
suited for numerous applications including
on-air television sports broadcasting. The
Model 210 integrates all on-air, talkback,
and cue audio signal routing into one compact system. Ease of use, configuration
flexibility, and sonic excellence are some
of the unit’s highlights.
Figure 1. Model 210 front panel
The Model 210 is compatible with most
broadcast and audio system environments.
Standard connectors are used to interface
microphone, headphone, talkback, and IFB
signals. Whether it’s microphone switching, talkback output, or headphone cue
feed, superior audio quality is maintained.
A microprocessor provides the Model 210’s
logic power, allowing exacting control of
the unit’s operation. A range of configuration choices allow the desired operating
parameters to be easily selected. While
flexible, the user is presented with an easyto-use set of controls and indicators.
A truly next-generation product, extensive
research into the needs and desires of field
production personnel was integral to the
Model 210’s creation. While primarily targeted for on-air television applications, specialized features are included to allow the
Figure 2. Model 210 back panel
Model 210 to be used in a variety of other
audio applications. These include on-air
radio broadcasting, stadium announcement, and voice-over/narration booths.
System Features
Microphone Input
A high-performance microphone preamplifier circuit provides low-noise/lowdistortion amplification over a 20 to 60 dB
gain range. The gain is adjustable in
10 dB steps. The input is compatible with
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balanced dynamic or condenser microphones. The microphone power source
is 48 volts nominal and meets the worldwide P48 phantom power standard. The
preamplifier’s gain can also be set for 0 dB,
allowing a line-level audio signal to be connected. This could prove useful in special
applications such as when an external preamp or mic processor is being used.
An LED indicator serves as an aid for optimizing the setting of the preamplifier’s gain.
The output of the microphone preamplifier
is used by the main output as well as being
routed to the compressor circuit that supports the talkback function.
Main and Talkback Outputs
The Model 210 provides one main and one
talkback output. The main output is designed to serve as the on-air, stadium
announcement, or other primary audio
feed. With a nominal level of –2 dBu, it is
designed as a fully professional interface
with high output capability, low distortion,
and low noise. It features a high-quality
transformer expressly designed for driving
long broad- cast cable runs. The talkback
output is intended to provide production
trucks, control rooms, or support personnel
with a talent-originated cue signal. The talkback output is transformer-coupled with a
+4 dBu nominal signal level. It contains resistors in series with its output connections,
allowing the talkback output from multiple
units to be directly summed (combined).
For non-on-air applications, a special Model 210 feature can be enabled, placing the
unit in a “production” mode. This allows the
main output to be used as a second talkback output. In this configuration the unit
can be even more powerful when used in a
live event application, such as serving as a
master console for a production director.
Dynamic Range Control
A studio-quality compressor circuit is
provided to control the dynamic range
of the signal coming from the microphone
preamplifier. Far from a simple “clipper,”
the circuit utilizes a sophisticated lasertrimmed voltage-controlled-amplifier (VCA)
integrated circuit for quiet, low-distortion
level control. The signal from the compressor is always used by the talkback output.
In addition, the audio source for the main
output can be selected to be either the
output of the microphone preamplifier or
the output of the compressor. While possibly not appropriate for major on-air situations, having dynamic range control of the
main output can offer increased effectiveness for many applications. These could
include stadium announcement positions,
sports events using nonprofessional on-air
talent, and situations where cable crosstalk is of concern.
User Controls and Status
Indicators
Two pushbutton switches, three LED indicators, and two rotary controls provide
the user with a clear, easy-to-use interface.
One pushbutton switch controls the status
of the main output. This is the audio output intended for on-air, announcement, or
other primary uses. Two LEDs display the
on/off status of the main output. A second
pushbutton switch controls the status
of the talkback output. This is the audio
output used to communicate with producers, directors, spotters, or other behindthe-scenes production personnel. A status
LED is associated with the talkback button. Two rotary controls allow the user to
adjust the level of the headphone output.
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Flexibility
A large part of the Model 210’s unique
power is the ability to configure the
operation of the main output and
talkback functions. To meet the needs
of the many specific broadcast and production applications, a variety of button
operating modes is available. The main
output button can be selected to operate
from among four modes. In the “push-tomute” mode the button performs a momentary mute of the main output. In this
way a “cough” button function is created,
something typically required for television
sports broadcasting. In the “push-to-talk”
mode the button provides a momentary
active function for the main output. This
mode would be appropriate for applications such as stadium announcement. An
alternate action “latching” configuration
allows the button to enable or disable the
main output as desired. This is useful in
radio broadcasting, announce-booth, or
voice-over applications. The fourth mode
provides a hybrid function, supporting
both push-to-talk and tap-to-enable/
tap-to-disable operation. This operation
is similar to that found in many broadcast
intercom system user stations.
The button associated with the talkback
function can be configured to operate
from either of two modes. One of the
modes supports a “push-to-talk” function.
This is typically used for on-air broadcast
applications. The other mode provides
a hybrid function, the operation of which is
discussed in the previous paragraph. The
hybrid mode is especially useful when the
Model 210 is used in a production-support
application.
IFB Input
A broadcast-standard “wet” (DC with
audio) IFB circuit can be directly connected to the Model 210’s IFB input.
Originated by sources such as the RTS™
4000-series IFB system or IFB interface
devices from Studio Technologies, the
connected IFB circuit can provide the DC
power to operate the Model 210 as well as
two channels of cue audio.
Cue Sources
The Model 210 allows the two audio
sources associated with the IFB input to
be selected for routing to the headphone
output. Originating in production trailers,
control rooms, or remote locations, these
unbalanced sources normally provide DC
power and program-with-interrupt audio
on one channel and program-only audio
on the other. Each source can be individually assigned to the left channel, right
channel, or both left and right. This allows
a wide variety of stereo and mono headphone mixes to be created.
Some applications may benefit by being
able to connect standard line-level audio
signals to the Model 210. To meet this
need one or two optional line input cards
can be installed in the Model 210’s back
panel. Each card provides a 3-pin female
XLR connector and transformer-isolated
+4 dBu nominal input circuit. Each source
can be individually assigned to the left
channel, right channel, or both left and
right.
Headphone Output
Two rotary controls are provided for user
adjustment of the headphone output
levels. For application flexibility the actual
function of the two “pots” is configurable.
For traditional on-air sports applications
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they can be selected to the dual-channel
(“level/level”) mode which provides
independent control of the left- and rightchannel volume. For use with dualchannel cue signals, or to support user
preference, the stereo (“level/balance”)
mode can be selected. In this mode one
control adjusts the overall level of both
the left and right channels, while the other
allows adjustment of the left/right level
balance. To help minimize the chance of
broadcast cues being missed, both level
control modes can be configured so that
a minimum headphone output level is
maintained. Alternately, the headphone
output can be set to fully mute when the
controls are at their minimum position.
Provision has been made to support applications where a monaural cue feed is
desired. A configuration switch allows the
summing (combining) of the selected left
and right headphone sources. In addition
to creating a dual-channel mono output it
also allows the level controls to be configured as a simple 2-channel mixer.
The headphone output was designed
to meet the needs of contemporary headphones and headsets. Specifically, the
output circuits act as voltage, rather than
power, drivers. In this configuration they
can provide high output levels with very
low distortion and noise, along with minimal current consumption. The output circuits are configured to safely drive stereo
or mono loads. This ensures that all types
of headphones, headsets, and earpieces
can be directly connected.
Audio Quality and Protection
The Model 210’s circuitry is carefully
tailored to provide excellent audio performance. Professional-quality components
are featured throughout. For reliability
all audio routing is performed using solidstate devices. In all critical audio paths,
“clickless” electronic switches provide
noise-free control. All audio inputs and
outputs make extensive use of protection
components. This limits the chance of
damage from ESD and other undesirable,
yet real-world, hazards.
Power Sources
The Model 210 can derive its operating
power from either the IFB input or an
external nominal 24 volt DC source. For
redundancy, both power sources can be
connected simultaneously. An internal
switch-mode power supply ensures that
all Model 210 features are available when
the unit is powered by either source.
The Model 210 is compatible with IFB
circuits provided by most standard broadcast systems. However, maximum performance can often be obtained by using the
IFB interface devices available from Studio
Technologies. Single-channel and fourchannel units are available, each providing
high-quality audio along with an excellent source of DC power. They’re directly
compatible with most matrix intercom systems, as well as standard line-level audio
signals. Refer to the Studio Technologies
website for details.
Relay Contact
The Model 210’s circuitry includes a
general-purpose relay contact allowing
specialized configurations to be created.
Under software control, the form-A (normally open) solid-state relay contact can
be configured to follow the state of either
the main or talkback output functions.
Taking advantage of the locations provided for additional XLR connectors, a
technician may easily implement a variety
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Page 8 Studio Technologies, Inc.
of functions such as mic active indication,
audio muting during talkback, or audio
insertion control.
Configuration
Model 210 configurations are made
using a number of DIP-type switches. One
8-position switch array is used to set the
gain of the microphone preamplifier, the
on/off status of phantom power, and the
headphone stereo/mono mode. Another
8-position switch array configures which
of the IFB and auxiliary audio sources are
routed to the headphone output. A third
8-position switch array communicates the
desired operating modes to the microprocessor. All switches are accessible via the
bottom of the Model 210’s enclosure; the
unit does not have to be disassembled.
Changes made to any of the configuration
parameters become active immediately.
To prevent unwanted access to the configuration switches a security panel, included
with each unit, is attached to the bottom of
the enclosure.
Connectors
The Model 210 uses standard connectors throughout. The microphone and IFB
inputs use 3-pin female XLR connectors.
The main and talkback outputs use 3-pin
male XLRs. A ¼-inch 3-conductor jack
is used for the headphone output. The
external source of 24 volt DC power is
connected by way of a 2.1 x 5.5 mm
“locking” coaxial power jack.
In the world of broadcast and production
audio it’s fair to say that applications vary
widely. To this end, one or two additional
XLR connectors can easily be mounted
into the Model 210’s back panel. Multiple
3-position “headers” located on the Model
210’s circuit board provide technician
access to all input and output connections. Using a factory-available interface
cable kit allows a Model 210 to be optimized to meet the exact needs of specific
applications. For example, some applications may prefer to use a multi-pin XLR
connector to interface with a headset.
This can easily be accomplished by adding the appropriate 5-, 6-, or 7-pin XLR
connector and making a few simple connections. Other applications may benefit
from having “mult” or “loop-through” connections, something easily incorporated
into a Model 210. One or two optional line
input cards, as previously discussed, can
also be mounted in the spare XLR connector positions.
200-Series Announcer
Console Products
The Model 210 is just one in a series of
announcer console products available
from Studio Technologies. For applications
that require an alternate set of features the
other products in the 200-series should be
reviewed. Complete information is available on the Studio Technologies website.
Installation and Setup
In this section interconnections will be
made using the input and output connectors located on the Model 210’s back
panel. Microphone input, IFB input, main
output, and talkback output signals are
interfaced by way of 3-pin XLR connectors. A ¼-inch 3-conductor phone jack is
provided for the headphone output. A 2.1
x 5.5 mm coaxial jack allows connection
of an external 24 volt DC power source.
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System Components
Included in the shipping carton are the
following: Model 210 Announcer’s Console, user guide, button label sheet, and
24 volt DC power supply.
Microphone Input
The Model 210 is compatible with balanced dynamic and condenser microphones. Depending on the application,
the microphone may be part of a headset,
or be an independent handheld or standmounted model. The Model 210’s 48 volt
nominal power source will support essentially all phantom-powered microphones.
The quality of the Model 210’s microphone
preamplifier and associated circuitry is
such that special applications may benefit
from using “high-end” microphones. If
selected appropriately, models from manufacturers such as AKG, Beyer, Neumann,
Sennheiser, and Shure will perform very
well in Model 210 applications.
The microphone input is also compatible
with line-level audio sources. This allows
the output of an external microphone preamplifier, microphone processor, or audio
console to be directly connected. When
the configuration DIP switches are set for
0 dB (no gain) the nominal level of the
source audio signal should be approximately –2 dBu.
Microphone interconnection is made
by way of a 3-pin female XLR connector which is located on the Model 210’s
back panel. The mating connector (male)
should be wired so that pin 2 is signal
high (+ or hot), pin 3 is signal low (– or
cold), and pin 1 is shield. It’s possible that
an unbalanced microphone will also work
correctly. In this case, the mating connector (male) should be wired so that pin 2
is signal high (+ or hot), and signal common/shield is connected to both pins 1
and 3.
The Model 210 is not compatible with
unbalanced “electret”-type microphones
that require a source of low-voltage DC
for operation. These microphones, sometimes found in low-cost headsets, are
not generally suitable for on-air or other
demanding applications.
As of the writing date of this user guide,
the Sennheiser HMD 26 headset is very
popular for on-air sports broadcasting
use. A fine product, it works very well with
the Model 210. Note that adding the suffix “-XQ” to the headset’s full part number
(HMD 26-600-XQ) specifies a 3-pin male
XLR connector for the dynamic microphone and a ¼-inch 3-conductor plug for
the stereo headphones. This configuration is very useful, allowing the headset
to work directly “out of the box” with the
Model 210.
If the writer may digress for a moment
to recount a story… an audio dealer
once shared a secret with me concerning
headsets. He loved selling the “lower-end”
(less expensive) models of name-brand
headsets, which he did by the veritable
“boatload.” Why? Because these usually
broke soon after going into service! He
knew that on a regular basis he’d receive
orders for more of them. Had these
users, from the beginning, purchased only
premium-quality headsets, their total cost
of ownership would have been much less.
Enough said…
Headphone Output
The Model 210’s headphone output
is compatible with stereo or mono
headphones, headsets, or earpieces.
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Connecting devices with a nominal impedance of 100 ohms or greater is preferred.
This shouldn’t prove to be an issue as essentially all contemporary devices already
meet this condition.
Devices are connected to the headphone
output by way of a ¼-inch 3-conductor
phone jack located on the Model 210’s
back panel. As is standard for stereo
headphones, the left channel is connected
to the “tip” lead of the ¼-inch headphone
jack. The right channel is connected to
the “ring” lead of the jack. Common
for both channels is connected to the
“sleeve” lead.
Devices with ¼-inch 2-conductor “mono”
plugs can also be used with the Model
210’s headphone output. In this arrangement only the tip lead (left channel) will
be active. The 2-conductor plug will physically connect (“short”) the ring lead
(right channel) to the sleeve lead (common). Technically this won’t damage
the circuitry associated with the rightchannel headphone output. (51 ohm
protection resistors are electrically in
series with the headphone output circuits.)
However energy will be wasted if an
audio signal coming out of the right channel goes into a “dead short.” There is a
simple solution to this issue. No audio
source should be assigned to the rightchannel headphone output. Refer to the
Configuration section of this user guide
for details.
Main Output
The main output is intended to be the
“on-air” signal that connects to the input
of an audio console. The output is transformer balanced with a nominal signal level of –2 dBu. The actual level will depend
on the gain setting of the microphone
preamplifier, sensitivity of the microphone,
and how loudly the talent speaks into the
microphone. The transformer used in the
main output is intended for professional
broadcast applications. It has a low source
impedance and can drive lengthy cable
runs with no difficulty. It is capable of driving 600 ohm loads but performs best with
loads of 2 k ohms or greater. (This should
not prove to be an issue as virtually all contemporary audio equipment has a relatively
high input impedance.) As the secondary
winding of the output transformer connects directly to the main output connector,
care should be taken so that DC voltage is
never present on the interconnecting cable.
The main output is interfaced by means
of a 3-pin male XLR connector located on
the Model 210’s back panel. The interconnecting cable’s mating connector (female)
should be wired so that signal high (+ or
hot) is on pin 2 and signal low (– or cold) is
on pin 3. The cable’s shield can be connected to pin 1, but it will have no function.
To limit the chance of grounding interaction
between the Model 210 and connected
equipment, pin 1 on the main output’s
connector is isolated from any point in the
Model 210. The fact that pin 1 “floats” will
minimize the chance of hums, noises, or
buzzes being present on the equipment
connected to the main output.
Talkback Output
The talkback output is intended for connection to control rooms, production trailers,
or other locations where talent- originated
voice cues are required. The talkback output is transformer balanced with a nominal
level of +4 dBu. To enhance talkback
audio quality, the compressor circuit
controls the dynamic range of the signal
coming from the microphone preamplifier.
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For protection against accidental connection to cables that have DC power present,
the talkback output is capacitor coupled.
In series with the talkback output leads
are 300 ohm resistors, making the effective output impedance approximately 600
ohms. These resistors create a passive
summing network, allowing talkback outputs on multiple Model 210 units to be
connected together.
The talkback output is connected by way
of a 3-pin male XLR connector which is
located on the Model 210’s back panel.
A mating connector (female) should be
prepared so that signal high (+ or hot) is
expected on pin 2. Signal low (– or cold)
should be expected on pin 3. The cable’s
shield can be connected to pin 1. But, like
the main output, in order to minimize the
chance that ground-interaction problems
will arise, pin 1 of the talkback output
connector is isolated from the Model 210’s
chassis and circuitry. By making
pin 1 “float,” the often-feared “ground
loop” problem shouldn’t arise.
The talkback output is intended to drive
lengthy cable runs that are frequently part
of a remote broadcast application. While
the output circuitry is not intended to be
“on-air” quality, overall audio performance
should be very good. Devices connected
to the talkback output can range from
amplified loudspeakers to analog inputs
on intercom systems, and input channels
associated with audio consoles. Connecting the talkback output to devices that allow easy control of the signal level can be
helpful. For example, connecting to a spare
input channel on an audio console provides the flexibility to add gain or attenuate
as required. A talkback-associated output
connection on the audio console can then
connect to the final destination(s).
As previously mentioned, the talkback
outputs on multiple Model 210 units can
be directly connected together. Using
a simple “Y” or “W” cable, this passive
summing (adding together) of talkback
signals allows one audio cable to serve as
a master talkback path. A side effect from
using this passive summing technique
is that signal attenuation will occur. The
audio quality won’t suffer, but an audio
“pad” is created. If two talkback outputs
are connected together, a signal attenuation of 6 dB can be expected. Connecting
three talkback outputs together will result
in 9.5 dB of attenuation. And four talkback
outputs “multed” together will lead to
12 dB of attenuation. In most cases this
attenuation won’t pose a problem. Typically a device that receives the talkback
signal, such as an amplified loudspeaker,
will have an adjustable input sensitivity.
IFB Input
The Model 210’s IFB input is designed to
directly connect with “wet” (DC-biased)
IFB circuits. These circuits provide DC
power and one or two channels of audio
over a standard 3-conductor microphonestyle cable. Typically, the IFB circuit’s
interface connector is a 3-pin male XLR
wired so that common is on pin 1, DC with
channel 1 audio is on pin 2, and channel
2 audio is on pin 3. Some IFB circuits may
only have one audio channel. In this case,
audio will generally be on pin 3 with pin 2
providing only DC power.
The power supplied by an IFB circuit,
normally in the range of 28 to 32 volts DC,
is usually sufficient to operate the Model
210’s circuitry. The acceptable input range
is 24 to 32 volts, with a required current
of 105 milliamperes. Note that the specified input voltage is given when measured
Issue 5, September 2012 Model 210 User Guide
Page 12 Studio Technologies, Inc.
directly at the Model 210’s IFB input connector, not at the source of the IFB circuit.
The one or two audio signals provided
by the IFB circuit can serve as the audio
sources for the headphone outputs.
In North American field and in-studio
broadcast applications it is common to
find RTS 4000-series IFB equipment
being used to provide the IFB circuits.
The Model 210 can be directly connected
to, and function correctly with, one of
these circuits. For reliable operation,
especially when using lengthy cable runs,
it’s strong-ly recommended that no other
device be connected to a 4000-series IFB
circuit that is specified for connection to a
Model 210. This requirement is due to the
current-limited DC source that is supplied
by the 4010 IFB Controller.
With 4000-series IFB circuits channel 1
(XLR pin 2) provides program audio that
is “interrupted” with cue signals. This
channel is sometimes referred to as “program-with-interrupt.” It’s important to note
that the program audio source fully mutes
whenever directors or producers are communicating with on-air talent. Channel
2 (XLR pin 3) of the IFB circuit provides
a “program-only” audio feed. It is never
interrupted with cue signals.
While the Model 210’s IFB input was
designed for connection to a “wet” IFB
circuit, it’s also possible to connect linelevel audio sources. Please refer to the
Technical Notes section of this user guide
for details.
unit. The center pin of the jack is the positive (+) connection. While the requirement
for the external source is nominally 24
volts, correct operation will take place
over a 20 to 30 volt range. The Model 210
requires 70 milliamperes at 24 volts DC
for correct operation. Included with each
Model 210 is a 24 volt DC external power
supply. The power supply’s DC output
cable has been terminated with a Switchcraft® S760K coaxial power plug. This
“locking” type of plug correctly mates
with the Model 210’s 24 volt DC input jack.
The locking feature is important, allowing
the external power source to be securely
attached to the Model 210.
As previously discussed in this user guide,
an IFB circuit connected to the IFB input can serve as the Model 210’s power
source. Alternately, an external 24 volt
DC source can be connected. For redundancy, both the IFB circuit and the external source can be connected at the same
time. If one or the other becomes inoperative, the remaining source will provide all
Model 210 power.
Note that if both an IFB circuit and an
external 24 volt DC source are connected,
power will be drawn only from the external source. This minimizes the chance
that lengthy cable runs or other IFB circuit
issues will impact Model 210 operation.
Whichever device is providing power,
audio signals from the IFB circuit can still
serve as the audio sources for the headphone output.
External Power Input
An external source of 24 volt DC power
can be connected to the Model 210 by
way of a 2.1 x 5.5 mm coaxial power jack
which is located on the back panel of the
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Pushbutton Labeling
The two pushbutton switches used in
the Model 210 were selected for several
reasons. Foremost was the fact that they
are highly reliable, using gold-plated
contacts for long life in less-than-ideal
environments. A second reason was that
applying customized labels to the button
caps would be very simple. The labels, text
printed on clear material, are placed under
the clear caps on the top of the buttons.
From the factory the left button is labeled
COUGH and the right button is labeled
TALKBACK. This was selected to be
appropriate for many on-air applications
in English-speaking locations. But it’s expected that these may need to be changed
to meet the needs of specific applications.
As a “head start” for some applications,
a clear sheet with a number of commonly
used button designations printed on it is
included in the shipping carton. These
were created at the factory using a standard personal computer graphics program
and laser printed onto 3M CG3300 or
equivalent transparency film. The desired
button labels can be cut out with a pair of
scissors, following the printed guide lines
that indicate the required size.
The clear lens on top of each button cap
can be removed with a fingernail or small
screwdriver. Be certain not to scratch the
button if a screwdriver or other small tool
is used. The clear label can be removed
and replaced. The button cap is then
snapped back into the top of the button
housing using finger-pressure only. No tool
is required to replace the button cap.
Configuration
For the Model 210 to support the needs
of specific applications a number of operating parameters must be configured.
These include microphone preamplifier
gain, phantom power on/off, headphone
source selection, headphone stereo/
mono mode, and operating modes. Three
8-position DIP-type switch assemblies are
used to establish the desired configuration. These switch assemblies are referred
to as SW1, SW2, and SW3, with individual
switches designated as SW1-1, SW1-2,
etc. The switch assemblies are accessed
through openings in the bottom of the
Model 210’s enclosure. The enclosure
does not have to be disassembled to gain
access to the switches.
To prevent unauthorized personnel from
changing the configuration settings, a security plate is attached to the bottom of the
Model 210’s enclosure. For convenience,
the security plate provides a summary of
the configurable parameters and related
information. Refer to Appendix A for a representative view. The security plate is held
in place by means of four rubber bumpers
(“feet”) that have built-in screws. Using
your fingers, remove the four bumpers so
that the plate can be removed. Refer to
Figure 3 for a detailed view of the configuration switch assemblies.
If you need to make your own labels the
process is quite simple. Use a personal
computer to create the desired text. The
finished label size should be 0.625-inches
(15.8 mm) square. The completed artwork
can then be printed on transparency film
sheets using a laser or inkjet printer. These
sheets are readily available from most
office supply stores. A pair of scissors or
an X-ACTO® knife will complete the task.
Issue 5, September 2012 Model 210 User Guide
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Microphone Preamplifier Gain
and Phantom Power
Five switches are used to set the gain of
the microphone preamplifier. One switch
is used to select the on/off status of the
phantom power supply.
Figure 3. Bottom view of Model 210 showing
configuration switches and compressor active
LED
Microphone Preamplifier Gain
Switches SW1-1 through SW1-5 are used
to select the gain of the microphone preamplifier. The choices are 20, 30, 40, 50,
60 dB; 0 dB (no gain) is also available.
Only one switch should be enabled at a
time. There’s no problem changing the
gain setting while the unit is operating.
Audio clicks or pops might occur during
gain transitions, but this shouldn’t be a
major issue as long as associated monitor
loudspeakers are temporarily attenuated
or muted.
Selecting the correct amount of gain for
an application might take a little experimentation. The goal is to bring the mic’s signal
Figure 4. Microphone preamplifier gain switch
settings
up to line level, nominally –2 dBu for the
Model 210’s main output. Operating at this
signal level will help to ensure the delivery
of “clean” audio to the connected device.
It’s also acceptable to connect a live-level
audio source to the microphone input. In
this case selecting 0 dB (no gain) would
be appropriate.
The output of the Model 210’s microphone
preamplifier is used by the main output
and, by way of the compressor circuit, the
talkback outputs. So creating a nice “hot”
signal will help maintain audio quality, specifically a high signal-to-noise ratio, when
driving the often-lengthy cable runs.
Unfortunately, there’s no “perfect” gain
setting that this guide can recommend.
The two issues that impact the setting are
output sensitivity of the connected microphone and the acoustical output level of
the microphone’s user. With some headset
microphones, such as the Sennheiser HMD
26, selecting an initial setting of 40 dB is
appropriate. Users who speak loudly might
need to have the gain reduced to 30 dB.
Quiet users might need 50 dB of gain.
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An LED indicator is provided as an aid
in correctly setting the gain of the microphone preamplifier. Red in color, this LED
is located adjacent to switch assembly 1.
It is visible by observing the bottom of the
Model 210’s enclosure when the security
plate has been removed. Technically, this
red LED lights whenever the compressor
circuitry is controlling the dynamic range
of the signal coming from the microphone
preamplifier. The threshold is set to be
2 dB above the Model 210’s nominal internal operating level. So a good “rule of
thumb” is to adjust the gain of the microphone preamplifier such that the compressor active LED lights (“flashes”) when the
connected microphone is sending signal
peaks. During normal operation the LED
should not remain fully lit when audio is
present on the mic input.
Note that if no gain switch is set to its
active (on) position the preamplifier
will operate at unity (0 dB) gain. This is
provided for compatibility when line-level
signals need to be connected to the
microphone input. But with a microphone
connected as the input source one should
never use the 0 dB setting. The issue is
that with no gain added to the microphone
input signal, the relative noise floor on the
main and talkback outputs will be much
too high. These outputs are designed for
handling line-level signals, expecting to
receive the output of the mic preamplifier.
Relay Contact Mode
Switch SW1-7 configures the operating
mode of the relay contact function.
It’s important to remember that the compressor active LED is used to assist in setting the gain to the optimal value. It doesn’t
necessarily indicate that the main output’s
signal is being compressed. Unless specifically configured to perform otherwise, the
output of the compressor is only used for
the talkback output.
It’s expected that the 20 and 60 dB gain
settings will not often be used. But there
are always exceptions and that’s why they
were included. It’s possible that with a very
“hot” microphone, such as a phantompowered condenser-type, 20 dB of gain
could be correct. It’s also possible that a
microphone with a very low-level output,
such as a ribbon-type, would need 60 dB
of gain. But in general, the 30, 40, and
50 dB gain settings will serve most
applications.
Figure 5. Relay contact mode switch settings
Two modes are available:
• Follows main output status: In this mode
the relay contact will follow the status of
the main output. Specifically, the relay
contact will close (short) whenever the
main output is active.
• Follows talkback output status: In this
mode the relay contact will follow the
status of the talkback output. Specifically, the relay contact will close (short)
whenever the talkback output is active.
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Phantom Power On/Off
The Model 210 can provide 48 volt nominal phantom power to the microphone
input. Switch SW1-8 controls whether or
not phantom power is active. By phantom
power’s very nature it could be left applied
to the microphone input at all times. But
generally people prefer to turn it off unless
required for a specific microphone.
Figure 6. Phantom power switch settings
Headphone Source Selection
Switch assembly SW2 is used to configure
the source or sources that are routed to
the stereo headphone output. The headphone sources are IFB channel 1, IFB
channel 2, auxiliary input 1, and auxiliary
input 2. The IFB channels are provided by
way of the IFB input connector located on
the Model 210’s back panel. The auxiliary
inputs are available only if the optional
line input cards have been installed or a
special Model 210 configuration has been
implemented.
Each of the available input sources can
be assigned to the headphone output’s
left channel, right channel, or both the
left and right channels. The Model 210’s
circuitry allows any combination of input
assignments to be made. For example,
consider the situation where a singlechannel IFB system, with both program
and interrupt audio on pin 3, is connected
to the Model 210. In this case it may be
desirable to assign this IFB signal to both
Figure 7. Left and right channel headphone
source selection settings
the left and right headphone channels.
This would entail setting switches SW2-2
and SW2-6 to their on positions. All
other switches would remain in their
off positions.
A more complex application might have
a 2-channel IFB circuit connected to the
Model 210, with an optional line input
card installed and line-level audio from
a golf event “spotter” connected to that.
In a case such as this, it would be typical for IFB channel 1 to be assigned to
the head-phone’s left channel, IFB channel 2 assigned to the right channel, and
auxiliary input 1 also assigned to the right
channel. This would allow both IFB channel 2 and “spotter” audio to be heard in
the head-phone’s right-channel output. To
achieve this would require that switches
SW2-1, SW2-6, and SW2-7 be placed in
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their on positions. Note that using another
Model 210 at the “spotter” location could
also prove effective. It would provide all
the necessary microphone preamplifier,
talkback routing, and headphone monitoring resources.
Note that in some cases a user may
wish to wear a headset or a pair of headphones in a left/right orientation opposite
of what’s usual. In this situation the transducer designated for the left ear would
actually supply audio to the user’s right
ear, and vice versa. A specific application
when this occurs is where on-air talent
needs to have a headset’s boom microphone come across the right side of their
face, rather than the more-typical left side.
In this case it’s important to select the
left- and right-channel headphone source
assignment accordingly. With the Model
210’s flexible source selection there’s no
reason why users, such as on-air talent,
shouldn’t have their cue sources assigned
correctly.
There may be cases where a monaural
“single-muff” headset or headphone will
be connected to the Model 210’s headphone output. In this case the desired
source(s) should be routed only to the left
channel. No sources should be assigned
to the right channel. This will eliminate the
short-circuit current that could occur when
a 2-conductor (monaural) plug is mated
with the Model 210’s 3-conductor (stereo)
headphone output jack.
Headphone Output Mode
Switch SW1-6 allows a monaural headphone output to be created. This is
accomplished by summing (adding) the
selected left- and right-channel cue signals. The combined signals are sent to
both the left- and right-channel headphone
Figure 8. Headphone output mode settings
output driver circuits. The outputs of these
circuits connect, by way of 51 ohm series
protection resistors, to the headphone
output jack.
The headphone output monaural mode
feature was specifically included so that
a special 2-channel headphone mix mode
can be created. By enabling the mono
mode, the two front-panel user level controls (“pots”) can be used to create the
desired “mix” of signals being sent to the
headphone output. Many applications,
especially in production settings, can
benefit from this capability. The desired
cue sources must be carefully assigned
to take advantage of the monaural mode.
The first cue source should be assigned,
using the DIP-type switches, to the left
channel. Its output level will be adjusted
by the left control. The second cue source
should be assigned to the right channel.
Its output level will be adjusted by the right
control.
There is one limitation related to the headphone mono output mode. It’s the fact
that the output will be 2-channel monaural. Whatever signal is present on the
headphone output’s left channel will also
be present on the right channel. A stereo
headphone mix can’t be created. But in
most cases this limitation won’t overshadow the benefit of being able to create
the mix. For signal-flow clarification please
review the block diagram located at the
end of this user guide.
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Operating Modes
The eight switches associated with switch
assembly SW3 are used to configure the
Model 210’s operating modes. Technically,
these switches “talk” to the micro-controller integrated circuit and associated software that give the Model 210 its “smarts.”
The software has been carefully designed
to provide a number of different ways in
which the unit can function. It’s critical to
carefully review the available options and
choose the ones that best meet the needs
of a specific application. Note that switches can be changed even while the Model
210 is powered up and operating. The
unit’s operating characteristics will change
in “real-time” in response to configuration
changes.
Main Output Button Mode
Switches SW3-1 and SW3-2 configure
how the main output button functions.
• Push to talk: In this mode the main out
put is normally muted. The main output
will become active whenever the button
is pressed and held.
• Alternate action: In this mode the main
output will change between its active
and muted state whenever the button
is pressed. Upon power up the main
output will be in its muted state.
• Hybrid: This mode is a combination
of push to talk and alternate action. It’s
similar to the way talk buttons function
on user stations associated with broadcast and production intercom systems.
If the button is pressed and held, the
main output will become active until
the button is released. If the button is
momentarily “tapped” the main output
will change state. Upon power up the
main output will be in its muted state.
Talkback Output Button Mode
Switch SW3-3 configures the way the talk
back output button functions.
-
-
Figure 10. Talkback output button mode settings
Figure 9. Main output button mode settings
Two modes are available:
There are four available modes:
• Push to mute: In this mode the main
output is normally active. The main output will mute whenever the button
• Push to talk: In this mode the talkback
output is normally muted. The talkback
output will become active whenever the
button is pressed and held.
is pressed and held. This is the “cough”
mode typically used for on-air sports
broadcasting applications.
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• Hybrid: This mode is a combination of
push to talk and alternate action. If the
button is pressed and held, the talkback output will become active until
the button is released. If the button is
momentarily “tapped” the talkback output will change state. Upon power
up the talkback output will be in its
muted state.
Headphone Output Operating Modes
The user is provided with two rotary level
controls (“pots”) that are associated with
the stereo headphone output. Switches
SW3-4, SW3-5, and SW3-6 are used to
configuration the way the controls function. With just these three switches a wide
range of operating modes can be configured. Carefully reviewing the capabilities of the available functions may prove
worthwhile.
Dual-Channel or Stereo Mode
Switch SW3-4 is used to select whether
the controls provide a dual-channel (“level/level”) or stereo (“level/balance”) mode
of operation. In the level/level mode the
two controls operate independently, each
controlling the level of one of the headphone output channels. This mode is
generally used for on-air broadcast applications where independent cue signals
are provided to the left- and right-headphone channels. In the level/balance
mode the left rotary control sets the overall
output level for both headphone channels.
The right rotary control is used to adjust the
balance (the relative levels) of the left and
right channels. This mode is generally best
suited for applications where a stereo cue
source is being provided.
Reverse Left/Right Mode
Switch SW3-5 is used to select whether the
rotary controls are in the normal or reverse
left/right mode of operation. When selected
to the normal mode, and level/level mode
is also selected, the left control adjusts the
level of headphone output’s left channel.
(This is the signal that appears on the tip
lead of the ¼-inch 3-conductor jack.) The
right control adjusts the level of the right
channel. When selected to the normal
mode, and the level/balance mode is also
selected, turning the balance control in the
counterclockwise direction increases the
perceived level of the left channel, and vice
versa.
As you may have already guessed, when
selecting the reverse left/right mode of operation everything is reversed! To be more
specific, when selected for reverse mode,
and the level/level mode is also selected,
the left control adjusts the headphone output’s right channel (output jack’s ring lead)
while the right control adjusts the left channel. When selected to the reverse mode,
and the level/balance is also selected, turning the balance control in the counterclockwise direction increases the perceived level
of the right channel, and vice versa.
Figure 11. Headphone control mode settings
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Figure 12. Headphone control operation
settings
The reverse mode is provided specifically
for cases where a headset’s left and right
ear pieces are placed on a user’s head in
a reverse orientation. This ensures that
the user is provided with a consistent
and easy-to-use set of headphone level
controls.
Minimum Level Mode
Switch SW3-6 is used to configure the
headphone output’s minimum level. In
the –40 dB mode the minimum headphone output level is 40 dB below
maximum. The headphone output channels will never fully mute. This ensures that
any audio signal present on the selected
Model 210 inputs will always be present
on the headphone output. In most on-air
broadcast applications this is the appropriate setting.
When the full mute mode is selected,
and the level/level mode is also selected,
moving either control to its fully counterclockwise position will cause its associated channel to fully mute.
When the full mute mode is selected,
and the level/balance mode is also selected, turning the level control to its fully
counterclockwise position will cause both
headphone channels to mute. Turning
the balance control to either its fully clockwise or fully counterclockwise position will
cause the appropriate channel to 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.
Main Output Source
Switch SW3-7 is used to select which
audio source is routed to the main output.
The choices are the output of the microphone preamplifier or the output of the
compressor circuit. For most on-air
applications the output of the microphone
preamplifier is the desired source. This
will provide the most natural audio quality
with the potential for a large amount
of dynamic range.
In some applications it may be desirable
for the output of the compressor circuit to
be routed to the main output. Appropriate
applications could include on-air broadcast situations where nonprofessional
talent is present. Controlling the dynamic
range of the audio signals on the main
output can limit the chance of cable crosstalk and equipment overload. Another typical application where using the output of
the compressor would be when the Model
210’s system mode is selected for production. In this case the main output would be
used as an additional talkback output and
dynamic range control could be beneficial.
Figure 14. Main output source settings
Figure 13. Headphone output minimum level
settings
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System Mode
Switch SW3-8 is used to configure the
overall operating mode of the Model 210.
Specifically, it determines how the main
output operates vis-à-vis the talkback output. Understanding how the two modes
impact overall system operation will ensure that correct operation and maximum
usability will occur. When selected to the
on-air mode, the main output will mute
whenever the talkback output is active.
The LED indicators associated with the
main output will light accordingly. The onair mode should be selected for all on-air
broadcast applications. It’s imperative that
the main output be muted whenever on-air
talent uses the talkback output to communicate with production personnel.
When the system mode is set for production, the main output is never muted in
response to the talkback output being
active. This mode allows the main output
to be used, for example, as an additional
talkback output. In this way the main and
talkback outputs can be used independently, with neither impacting the other.
This also allows both buttons 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!
Conclusion
Once the switches have been set to the
desired configuration, the security plate
should be reattached. The four rubber
bumpers should be hand-tightened only.
No tools should be used.
Operation
At this point the desired input, output,
and power connections should have been
made. The button labels may have been
revised. Finally, the configuration switches
should have been set. Normal operation
of the Model 210 can now begin. The
unit will begin functioning as soon as a
power source is connected. As previously discussed, the power source can be
provided by an IFB circuit, an external 24
volt DC power source, or both. It’s important to highlight the fact that the Model
210 is an active device. Audio signals will
not be present on the outputs if correct
power has not been supplied. Specifically,
the microphone does not passively “cut
through” to the main output connector!
Upon Model 210 power up, the three
status LEDs will light in succession as a
firmware “boot up” indication. The unit will
then begin normal operation. Depending
on the selected configuration, one LED
associated with the status of the main output may be lit. The user is now presented
with two buttons, three LEDs, and two
rotary controls. These are simple to operate and understand, as will be described
in the following paragraphs.
Figure 15. System mode settings
Pushbutton Switches and
Status LEDs
Two pushbutton switches are used to
control the main and talkback outputs.
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The way each operates depends on the
selected configuration. Three LED indicators are located adjacent to the buttons.
They reflect the status of the main and
talkback output functions.
Main Output Button and LED Indicators
The button on the left, factory labeled
as COUGH, functions according to the
selected configuration. Two LED indicators, located directly above the button, are
associated with the status of the main output. The green LED, located on the right,
is lit whenever the main output is active.
This could be considered as an “on-air” or
mic active indicator. At the least it should
serve as a “careful what you say” warning! If the Model 210’s system mode is
configured to on-air, the red LED, located
on the left, will be lit when the main output
is muted. This indicates that it’s safe to
speak as one sees fit.
If the Model 210’s system mode is configured to production, the red LED will never
light. This is to reflect the fact that the main
output button has now taken on a function
similar to that of the talkback output button. To clarify, when the Model 210 is set
to the production mode, the red LED will
never light; the green LED will light whenever the main output is active.
Main Output Button Modes
• Push to mute: If this mode is selected
the main output is normally active. The
main output will mute whenever the button is pressed and held.
• Push to talk: If this mode is selected
the main output is normally muted. The
main output will become active whenever the button is pressed and held.
• Alternate action: If this mode is selected
the main output will alternate between
its active and muted states whenever
the button is pressed. Upon power up
the main output will be in its muted
state.
• Hybrid: This mode is a combination
of push to talk and alternate action. It’s
similar to the way talk buttons function
on user stations associated with broadcast or production intercom systems.
If the button is pressed and held, the
main output will become active until
the button is released. If the button is
momentarily “tapped” the main output will change state. Upon Model 210
power up the main output will be in
its muted state.
Main Output vis-à-vis Talkback Activity
This short section applies only in the case
where the Model 210’s system mode is
configured for on-air and the main output
button mode is set to alternate action or
hybrid.
Talkback activity will always cause the
main output to be placed in its off state.
If the main output was in the “latched”
on state when talkback began, once talkback activity ends that state will resume;
the main output will again be in its on
(“latched”) state.
Talkback Output Button and LED
Indicator
The button on the right, factory labeled
TALKBACK, controls the talkback output.
The manner in which the talkback button
functions depends on the way it was configured. One LED indicator, green in color,
is located directly above the talkback button. It lights whenever the talkback output
is active. If the Model 210’s system mode
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is selected to on-air, whenever the talkback
function is active the main output will be
placed in the muted state. If the Model 210
is selected to the production mode, the
status of the talkback output will not impact
the main output.
control on the right is used to adjust the
level of the right channel. If configured
to the reverse left/right mode, the control
on the left side adjusts the headphone
output’s right channel. The control on
the right adjusts the left channel.
Talkback Output Button Modes
• Push to talk: If this mode is selected the
talkback output is normally muted. The
talkback output will become active whenever the button is pressed and held.
• Hybrid: This mode is a combination of
push to talk and alternate action. If the
button is pressed and held, the talkback
output will become active until the button
is released. If the button is momentarily
“tapped” the talkback output will change
state. Upon Model 210 power up the talkback output is will be in its muted state.
Headphone Output Level Controls
Two rotary controls (“pots”) are located
on the Model 210’s front panel and are
associated with the headphone output.
The way the controls function depends
on the selected configuration. One configuration parameter sets the controls to operate in a level/level or a level/balance mode.
Another parameter allows the left/right assignment of the controls to be reversed. A
third parameter selects whether the headphone output channels will maintain a minimum output level or can be fully muted.
Level/Level Mode
When set to the level/level mode, the
two controls operate independently. Each
control sets the output level of one channel
of the stereo headphone output. If configured to the normal mode, the control on
the left side is used to adjust the level of
the headphone output’s left channel. The
When in the level/level mode, and the
minimum output level is set for –40 dB,
turning each control to its fully counterclockwise position will place its respective
output level 40 dB below its maximum.
This setting ensures that talent will never
be fully “isolated” from potentially important cue signals. If present on the Model
210’s input and assigned to the headphone channels, some audio signal will
always be present on the headphone
output. If set to the full mute mode, turning
each control to its fully counterclockwise
position will cause its respective output
to fully mute.
Each level control has a mechanical step
(detent) that is located at the halfway
(50%) position of its rotation range. This
is intended to serve as an aid to Model
210 users. In an ideal installation, setting
the controls to their detent position will
result in a comfortable headphone output
level. The user, in response to a changing
operating environment, can then move
the level controls to get more or less level
as desired. The detent position will always
remain as a useful reference point. To
achieve this condition the audio level
on the connected IFB circuit, or auxiliary
input, will have to be calibrated as required. This is somewhat counter to the
usual mentality of just providing the user
with whatever level comes up by default.
Spending a few extra minutes “trimming”
the audio levels can result in much
happier, and more productive, talent.
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Level/Balance Mode
When set to the level/balance mode, the
two controls operate together to adjust
the desired headphone output level. The
control on the left adjusts the overall level
of both the left and right channels. The
balance control, located on the right,
adjusts the relative left/right level balance. In this mode the controls operate
in a manner reminiscent of a consumer
audio amplifier or receiver. If set to the
normal mode, rotating the balance control
in the counterclockwise direction reduces
the level of the right channel providing
the user with more perceived level in the
left channel. If set to the reverse mode,
rotating the balance control in the counterclockwise direction reduces the level
of the left channel providing the user with
more perceived level in the right channel.
center, detent position, making the level
of the left and right channels equal. In an
ideal installation, the level control can also
be set to its detent position and provide a
comfortable headphone output level.
This will allow the user, in response to their
preference or a changing environment, to
adjust the level and balance controls as
desired. The detent positions will always
remain as a useful reference point. To
achieve this condition the audio level on
the connected IFB circuit, or auxiliary
input, must be adjusted as required.
Spending a few extra minutes “trimming”
the connected audio levels, rather than
just providing whatever happens to come
up, should prove worthwhile. The result
will be talent that is more relaxed, and
an overall production that works more
smoothly.
When in the level/balance mode and the
minimum output level is set to –40 dB,
turning the level control to its fully counterclockwise position will place both headphone output channels to 40 dB below
maximum. This ensures that talent will
never be fully “isolated” from potentially
important cue signals. In addition, rotating the balance control to either its fully
clockwise or fully counterclockwise position will cause the applicable channel to
be 40 dB below its maximum. If set to the
full mute mode, turning the level control
to its fully counterclockwise position will
cause both the left and right channels to
fully mute. In addition, rotating the balance
control to either its fully clockwise or fully
counterclockwise position will cause the
applicable channel to fully mute.
Each control has a mechanical step
(detent) that is located at the halfway
(50%) position of its rotation range. The
balance control will typically be set to its
Technical Notes
Grounding and Shielding
As previously discussed in this user guide,
the pin 1 connections on both the main
and talkback outputs’ 3-pin male XLR connectors are “floating,” i.e., not connected
to anything within the Model 210’s enclosure. Some audio experts might take
offense to this, complaining that this
should have been left to the user or installer to be connected or disconnect as
desired. However, repeated field testing
found that floating pin 1 on the outputs
was the key to maintaining quiet audio.
From Fenway Park, to the Orange Bowl,
and then northwest to Husker Stadium,
lifting pin 1 did the trick.
A simple solution is available if an application does require that a ground be available on the main and talkback outputs’
Model 210 User Guide Issue 5, September 2012
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interconnecting cables. All Model 210
XLR connectors have a ground connection
that is made to the interfacing connector’s
metal “shell.” And most XLR connectors
have a pin or connection point available
to access its metal shell. By connecting
the cable shield to the mating connector’s
shell terminal, the common connection
typically found on audio interconnections
is created.
IFB Channel Crosstalk
By the very nature of its design, a standard “wet” IFB circuit is prone to exhibit
cross-talk between its two audio channels.
This occurs because the audio paths are
unbalanced (“single-ended”) and typically
transported on a single shielded twistedpair audio cable. The primary cause of
the crosstalk is the capacitance between
the wires in the cable pair. The greater the
capacitance, due to cable type and length,
the more crosstalk there will be. It’s not
surprising to find in sports broadcasting
venues that audio from one channel in
an IFB circuit can be heard “bleeding”
into the other channel. Does this generally
create a problem? No, as each channel
in an IFB circuit generally carries related
audio content. For example, on-air talent
hearing in their left ear a small amount of
program audio from channel 2 while an
interrupt from channel 1 is active, typically
wouldn’t perceive this as an issue.
There are several ways of reducing IFB
channel crosstalk. Probably the easiest
way is to use cable pairs that are not twisted. Twisted pairs are great for differential
(balanced) signals, but not so great for
unbalanced transmission. This is generally because the more twists in a pair the
greater the effective cable capacitance.
In a stadium or arena setting, choosing
standard “telco” pairs may actually work
better than “high-performance” audio or
data cable!
Another option is to use two cable pairs
for each IFB circuit. If the pairs are not
shielded the wiring is simple. Common
would be connected to one side of each
pair, and then signal from each channel
would connect to the other side of the
pairs. If the pairs also contain shields
the wiring could be done somewhat differently. One option is to connect common
to both cable shields, IFB channel 1 (DC
with audio) to one full pair, and IFB channel 2 to the second full pair. A better
option might be to have common connect
to both shields and one side of the pair
that serves IFB channel 2.
Other options are available if an application demands low crosstalk. If resources
in the broadcast or production facility
allow one method would be to run the
IFB circuits “dry” (no DC) and differential
(balanced). This would gain the benefits
of differential transmission, including minimizing the crosstalk. If optional line input
cards have been installed in the Model
210, the balanced line-level signals can be
directly connected. However, if it’s desired
to connect cue sources to the Model 210
using an IFB-type circuit, the line-level
audio signals will need to be “wetted up”
into standard IFB circuits. This is easily
accomplished using one of several highperformance IFB interface units from
Studio Technologies. For further information please refer to the Studio Technologies website.
IFB Audio Levels
The Model 210 is designed to operate
best with IFB audio levels that are nominally –10 dBu. This is the nominal level
Issue 5, September 2012 Model 210 User Guide
Page 26 Studio Technologies, Inc.
of most IFB systems, such as the RTS
4000-series. But actually having the correct level present on an IFB circuit is often
a “hit-or-miss” proposition. During field
testing of prototype announcer’s consoles,
Studio Technologies’ personnel found that
a wide range of nominal audio levels were
present on “real-world” IFB circuits. Many
were fine, being reasonably close to the
desired –10 dBu. But some were much too
low, while others were much too “hot.” We
observed one unfortunate baseball “color”
commentator being sent interrupt audio
signals so “hot” relative to program audio
as to almost make his ears bleed! This
situation should not have been allowed
to happen.
In defense of field technical personnel,
measuring the audio level of an IFB circuit
hasn’t traditionally been an easy proposition. But that situation has now changed.
After experiencing this condition in the
“field,” Studio Technologies’ engineers
were motivated to design the Model 72
Level Meter/Interface. This compact
device plugs directly into IFB and intercom
circuits and provides two useful functions:
level meters and “dry” audio outputs. Two
5-segment LED meters allow direct observation of the audio signal levels present on
IFB or intercom circuits. The display range
is optimized for the signal levels found on
these circuits, rather than traditional “VU”
scaling.
The Model 72 also provides two transformer-coupled “dry” audio outputs, one
for each IFB or intercom channel. These
outputs are useful for a variety of production and testing applications. For example,
the outputs can serve as the interface
between a traditional “wet” IFB system
and a wireless in-ear monitor system. The
outputs can also be connected to a monitor panel, allowing visual and aural monitoring of the IFB audio signals.
In conclusion, we’re sorry for this shameless promotion of the Model 72 Level
Meter/Interface! But necessity was definitely the “mother” when it came to the
unit’s invention. Working in the field
without such a device, we felt “blind” when
connecting to IFB circuits. That no longer
has to be the case and we think that you’ll
find owning one a very worthwhile investment. For further information please refer
to the Studio Technologies website.
Phantom Power
The Model 210 provides a 48 volt nominal
source of phantom power to support condenser-type microphones. It’s designed
to meet the P48 requirements as specified
in the IEC 61938 standard. The circuitry is
very simple: two 6.81 k ohm resistors provide a path from a 48 volt source to pins 2
and 3 of the microphone input connector.
The resistors and the power source work
together to provide 48 ±4 volts, up to a
maximum current of 10 milliamperes.
Symptoms of Insufficient
Power
A core part of the Model 210’s internal
circuitry is a switch-mode power supply
that produces +48 volts, +12 volts,
+5 volts, and –12 volts. This power supply
circuit works very well as long as it is “fed”
with sufficient input voltage and current.
“Sufficient” is defined as a minimum of
24 volts on the IFB input and 20 volts on
the external 24 volt DC input. The necessary current, 105 milliamperes for the IFB
input and 70 milliamperes for the external
input, must be supplied over their respective voltage ranges.
Model 210 User Guide Issue 5, September 2012
Studio Technologies, Inc. Page 27
It’s worth discussing what will happen if
either power source falls below its specified
minimum. Typically, if the Model 210 is being powered by an external 24 volt nominal
power source, normal operation will continue until the input falls to the 18-20 volt
range. As the input voltage drops below
this range the Model 210’s internal power
supply will have reduced stability, operating
in this manner until its low-voltage shutdown circuit halts operation. Note that as
the input voltage moves down from 24 volts
the input current will rise proportionately to
make up for the
loss of power.
If an IFB circuit is powering the Model 210,
maintaining the required voltage and current is more critical. Should the voltage or
current fall below the specified minimum,
the Model 210’s power supply circuit will
again become unstable. This will become
an issue as noise will be induced into
the IFB circuit’s audio signals. The reason
is simple: an IFB circuit “multiplexes”
3-conductors so that they carry both power
and audio signals. If sufficient amounts
of voltage and current are supplied to the
Model 210’s IFB input, the Model 210’s
power supply will draw a steady amount of
energy. This will not disturb the analog signals on pin 1 (common for DC and audio)
and pin 2 (DC and channel 1 audio). But if
the Model 210’s power supply is not supplied with sufficient energy (volts x amps)
it will try to draw what it needs from the IFB
circuit, becoming unstable in the process.
The IFB circuit’s audio signals will be corrupted by the power supply’s attempt to
draw enough power. Instead of nice clean
audio there will be squeaks, squeals, and
some awfully funky noises added. Again,
in a low-voltage or low-current situation,
no damage will be done to the Model 210’s
circuitry but correct operation will not be
possible.
In most cases maintaining the IFB circuit’s
required voltage and current shouldn’t be
a problem. But issues may arise due to
malfunctioning IFB circuit sources or
poor interconnect cabling. Typically, excessive cable length won’t be the cause
of problem. Generally, problems will be
caused by broken or damaged connector pins, dirty patch points, or damaged
(partially open) cable conductors. Measuring the IFB circuit’s voltage and current
draw directly at the Model 210’s IFB input
connector will quickly identify if there’s a
power issue.
And now for another shameless “plug”
for other Studio Technologies products:
Frankly, most devices that supply IFB
circuits for broadcast applications use
outdated technology that provides
mediocre performance. That’s why
Studio Technologies’ developed highperformance IFB interface units. These
products do an excellent job of providing
power and audio to connected devices
such as the Model 210. However, unlike other products, the power supplied
by these units’ IFB circuits maintain their
output voltage all the way to their full rated
current. The result is being able to power
more devices over longer cable runs. In
addition, the audio quality of these units
is superior. For further information please
refer to the Studio Technologies website.
LED Colors
As previously described, two LED indicators are associated with the main output
and are located directly above the main
output pushbutton switch. The red LED,
located on the left, is lit whenever the
main output is muted. The green LED,
Issue 5, September 2012 Model 210 User Guide
Page 28 Studio Technologies, Inc.
located on the right, is lit whenever the
main output is active. The thought process behind the color choices was that
red would relate to the main output being
muted (“stop”) while green would relate
to the main output being active (“go”). It’s
possible that these color choices may not
meet the needs of all users and applications. For example, it’s reported that one
European broadcaster typically uses these
two colors in the opposite fashion. Their
choice is to have the red LED lit whenever
the main output is active, warning the talent that they are “on-air.” The green LED
is lit whenever the main output is muted,
indicating to the talent that it’s “safe” to
say whatever they wish, about whomever
they wish to say it about!
For consistency, the LED associated
with the talkback button was selected to
be green. This lights whenever talkback is
active. It’s possible that some applications
may benefit from revising this LED color
too. While red is certainly one possible
choice, other colors are also a possibility
including amber, orange, or blue—these
days there are lots of choices available.
A qualified technician can easily revise
the LED colors to meet an application’s
exact needs. The process would begin
by disassembling the Model 210’s enclosure and detaching the pushbutton/LED
printed circuit board assembly. The LEDs
would then be unsoldered, removed, and
reinstalled (or replaced) in the desired
locations. To control the LED current and
set the brightness, a 825 ohm 1206-size
surface-mount resistor is electrically in
series with each LED.
For additional information about changing the LED colors, please contact Studio
Technologies’ technical support.
Travel Case
For portable applications it may be desirable to store and transport each Model
210 in a protective case. After much travel
with prototype announcer console units,
Studio Technologies’ personnel learned
to appreciate the Pelican Model 1450
case. Purchased with the foam interior
option, it does an excellent job of holding
one Model 210, its associated 24 volt DC
power supply, and documentation. Some
applications may benefit from selecting a
larger case that would also hold a related
headset, cables, etc. A larger case could
also be selected that would hold multiple
Model 210 units. Pelican sells their products through a dealer network, many of
which can be located via a web search.
Connecting Line-Level Inputs
The Model 210 is designed to directly
connect with “wet” broadcast IFB circuits.
However, there may be applications where
it would be helpful to also be able to connect standard line-level audio sources.
If it’s anticipated that line-level audio
sources will frequently need to be connected to the Model 210, one or two
line input cards can be installed. These
cards, available from Studio Technologies
and purchased separately (part number
31084), are mounted into the spare connector locations that are provided on the
Model 210’s back panel. Each line input
card contains passive circuitry, including
a 3-pin female XLR connector and a
10 k ohm to 10 k ohm isolation transformer. Once installed, balanced or unbalanced line-level audio sources can
be directly connected. Note that in cases
where only line-level signals are connected (no “wet IFB”) an external source of 24
volt DC power is required. This shouldn’t
Model 210 User Guide Issue 5, September 2012
Studio Technologies, Inc. Page 29
pose a problem as a 24 volt DC power
supply is included with each Model 210.
Each line input card kit contains a printed
circuit board assembly, an interconnecting
cable, and hardware. To install the kit is
very simple. The XLR connector is mounted into one of the spare connector locations on the Model 210’s back panel. This
secures the connector and associated
printed circuit board to the enclosure. The
interconnecting cable is then used to link
the card and the Model 210’s main printed
circuit board assembly. One end of the
cable is plugged into the line input card’s
3-position “header” that is labeled OUT.
The other end of the cable is plugged into
the desired 3-position header located on
the main printed circuit board. The header
associated with auxiliary input 1 is labeled
P11. The header associated with auxiliary
input 2 is labeled P10.
Note that the unused header remaining
on the line input card has its pins “multed”
with the leads on the 3-pin female XLR
connector. It is provided for other applications that may need it. Additional installation details are provided in the next
section of the user guide. Included is a
recommended connector labeling method
that is appropriate when line input cards
are installed.
For balanced audio sources the mating
connector (3-pin male XLR) should be
wired so that signal high (+ or hot) is
connected to pin 2, signal low (– or cold)
is connected to pin 3, and shield is connected to pin 1. Unbalanced sources
should be wired so that signal high is on
pin 2, and signal low/shield is connected
to both pins 1 and 3. If this results in hum
on the input, try connecting signal high to
pin 2, signal low/shield to pin 3, and pin 1
left unterminated (“floating”).
Several things are worth mentioning when
it comes time to actually using a line input
card. The input is transformer coupled
with a nominal input impedance of 10 k
ohms. Capacitors in series with the transformer’s primary provide protection again
accidental connection of a cable that has
DC voltage present on it. The nominal
input level is +4 dBu but should work correctly with signal levels down to nominal
–10 dBu. So that the rotary level controls
provide a more comfortable range of
operation during actual use, reducing the
level of a “hot” input signal by 3 to 6 dB
is preferred, versus having a full +4 dBu
nominal level.
Note that if one or two line input cards are
installed in a Model 210, both “dry” linelevel audio signals and a “wet” IFB circuit
can be connected at the same time. The
audio sources will be routed to the headphone outputs by way of the headphone
source configuration switches. Each of
the four possible audio sources can be
routed to the left-headphone output, the
right-headphone output, or both headphone-output channels. Details on how
to use these switches are provided in the
Configuration section of this user guide.
In “emergency” situations it’s possible to
connect line-level audio signals directly
to the Model 210’s IFB input connector.
This can be successfully done as long as
several limitations are taken into account.
The first limitation is that the 10 k ohm
input circuit presents an unbalanced load
to the source. In most cases this shouldn’t
pose a problem. If a balanced interconnection scheme must be maintained, an
in-line isolation transformer can be used.
A second limitation is that the audio level
presented must not exceed 0 dBu or signal “clipping” may occur. Prepare a 3-pin
Issue 5, September 2012 Model 210 User Guide
Page 30 Studio Technologies, Inc.
male XLR connector so that the line-level
audio source designated as IFB channel
1 is connected with signal high on pin 2
and low/shield on pin 1. The audio source
designated as IFB channel 2 should
be connected with signal high on pin 3
and low/shield on pin 1. With this connection scheme the nominal input level is
–10 dBu, the same as with an IFB circuit.
This may require that an external attenuator (“pad”) be used to reduce the level of
the connected signal. As expected, powering the Model 210 requires an external
source of 24 volts DC to be connected.
Additional Connectors
Two spare connector locations are provided on the Model 210’s back panel. From
the factory they contain blank plates that
can be readily removed and replaced with
a variety of XLR connectors. These spare
connector locations are specifically included so that a Model 210 can be customized
to meet the many specific needs that arise
in broadcast and related audio applications. Expected uses for these locations
include adding a 5-, 6-, or 7-pin XLR
connector to allow direct connection of
a broadcast headset. Other uses include
creating a “loop through” or “mult” functions for the talkback output or IFB input
connections. In addition, Studio Technologies offers an optional line input card that
mounts directly in a spare connector location. This was previously described in this
user guide.
The spare connector locations are compatible with the Neutrik DL-series of
connectors. For flexibility, versions are
available that provide from three to seven
contacts. For example, a compatible 3-pin
female connector would be Neutrik part
number NC3FD-L-1. To support headsets
the NC6FDS-L-1 is often used. This is a
6-pin female connector with the unique
Switch-craft 6-pin arrangement. The hardware that secures the blank plates to the
Model 210’s back panel is also intended
to secure the replacement connectors.
If connectors are added to the Model
210’s spare connector locations adding
labels to those connectors can be helpful.
For a great look it is recommended that
Brother® P-Touch ¼-inch (6 mm) labels be
created. Tape material that prints white text
on a black background works out well for
the Model 210. The Brother label cassette
number TX-3151, white on black, is appropriate for use with many of their printers.
In addition to the spare connector locations on the back panel, provision has
been made to allow easy interconnection
with the Model 210’s printed-circuit-boardmounted input and output connectors. This
was accomplished by including numerous
3-position male “header” connectors on
the Model 210’s circuit board. These headers, on 0.1-inch centers, are wired in parallel with the Model 210’s connectors. This
“no solder” solution makes customizing
a Model 210 a simple process. The headers, located on the Model 210’s printed
circuit board, are Molex® part number
22-23-2031. They mate with Molex housing
number 22-01-3037. To make the interconnection, separate crimp terminals are attached to loose wires and then “snapped”
into the housing. Molex part number
08-50-0114 specifies crimp terminals that
are appropriate for wires of 22 to 30 gauge.
These parts are available worldwide from
sources such as Digi-Key (www.digikey.
com).
To make the process of connecting to
the Model 210’s headers a simple task
Model 210 User Guide Issue 5, September 2012
Studio Technologies, Inc. Page 31
an interface cable kit, part number 31087,
is available from Studio Technologies.
Each kit includes five cable assemblies
and a length of heat-shrinkable tubing.
Each cable assembly consists of a mating
connector with three color-coded wires
attached. These wires, nominally 12 inches in length, allow convenient soldering
to a connector slated to be installed in a
spare location on the Model 210’s back
panel. For reference, the wire color for pin
1 is gray, pin 2 is yellow, and pin 3 is blue.
The heat-shrinkable tubing is provided so
that the connector solder cups can be insulated from each other. It will also provide
some strain relief to the solder joints. Be
certain to slip the desired length of tubing
over the wire prior to soldering a connection! (If the writer had a dollar for every
time he forgot to put tubing on a wire (or
slip on a connector shell) before making
a solder connection….)
connectors. The following list provides the
printed circuit board reference numbers
and text and their associated functions:
P3 (PHONES): Headphone output: pin 1
common; pin 2 tip (left); pin 3 ring (right).
P4 (MIC IN): Microphone input: pin 1
shield; pin 2 high; pin 3 low. Follows backpanel 3-pin female XLR pin assignment.
P5 (MAIN OUT): Main output: pin 1
shield; pin 2 high; pin 3 low. Careful! Backpanel 3-pin male XLR has pin 1 floating,
pin 2 high, pin 3 low.
P6 (TB OUT): Talkback output: pin 1
shield; pin 2 high; pin 3 low. Careful! Backpanel 3-pin male XLR has pin 1 floating,
pin 2 high, pin 3 low.
P7 (IFB IN): IFB input: pin 1 common; pin
2 DC with channel 1 audio; pin 3 channel
2 audio. Follows back-panel 3-pin female
XLR pin assignment.
The Model 210’s enclosure must be disassembled prior to installing connectors in
the spare locations. Four hex-head machine screws, two on the bottom front of
the enclosure and two on the back panel,
must be removed. A 5/64-inch hex driver
is required. The cover can then be carefully separated from the chassis, remaining attached by means of a flexible cable
assembly. This “flex-cable” assembly links
the main printed circuit board assembly
with the board assembly that contains the
pushbuttons and LED indicators. Ensure
that the flex cable is not damaged while
the Model 210 is being customized. For
easier access, the pushbutton/LED board
assembly can also be easily removed.
The 3-position headers on the Model
210’s main circuit board assembly are located close to their related input or output
P9 (DC IN 2): External 24 volt DC input:
pin 1 common; pin 2 +24 Vdc; pin 3 not
used. Back-panel 2.1 x 5.5 mm jack has
+24 Vdc on center pin. Header P8 is used
by the back-panel 24 Vdc jack assembly
and is electrically in parallel with P9.
Additional functions can be accessed
using these 3-position headers:
P10 (AUX IN 2):
Auxiliary input 2: pin 1
common; pin 2 unbalanced audio @
–10 dBu nominal; pin 3 not used.
P11 (AUX IN 1):
Auxiliary input 1: pin 1
common; pin 2 unbalanced audio @
–10 dBu nominal; pin 3 not used.
P12 (LIGHTING): Pushbutton backlighting: pin 1 not used; pin 2 button lamps;
pin 3 current limited 24 volts from external
24 Vdc input.
Issue 5, September 2012 Model 210 User Guide
Page 32 Studio Technologies, Inc.
P14 (SW INS): Remote switch input: pin 1
common; pin 2 main output control; pin 3
talkback output control.
P13 (DC OUT 1): Auxiliary DC output 1:
pin 1 common; pin 2 +12 Vdc; pin 3
–12 Vdc.
P20 (DC OUT 2): Auxiliary DC output 2:
pin 1 common; pin 2 +12 Vdc; pin 3
–12 Vdc.
P17 (RELAY CONTA
(normally open, not-shorted) solid-state
relay contact: pin 1 common; pins 2 & 3
relay contact (isolated from common).
CT): Form-A
Pushbutton Backlighting
For special applications, provision has
been made to allow illumination (“backlighting”) of the two pushbutton switches.
This may prove useful for applications
where adequate room lighting is not available. It can also serve in custom Model
210 configurations. Note that this is an
advanced feature, intended only to be
implemented by a qualified technician.
From the outset several limitations must
be discussed. The first is that button
backlighting is not intended to serve tally
applications. (A common connection to
power both lamps is provided; independent access to the lamp connections on
each button is not provided.) It is strictly
intended to provide a moderate amount
of illumination to the button’s clear lens
and associated labeling. The second
restriction is that power for the backlighting function cannot be provided by the IFB
input—there is simply not enough current available from a typical IFB circuit to
power the Model 210 and light the lamps.
However, power from the external 24 volt
DC source can be used. This requires that
this power source be connected whenever
backlighting is desired.
From the factory, lamps (“bulbs”) are
not installed in the pushbutton housings.
They are pluggable T-1 bi-pin type and
are simple to install. The mating socket
is accessed by removing the button’s
lens caps, graphic label, and back frosted
lens. Compatible incandescent lamps with
a nominal rating of 18 volts, 28 mA are
available from Studio Technologies (part
number 12030). Bulbs with other nominal
voltages should also be available from
electronics parts vendors. While compatible
LED-based lamps are probably also available, incandescent lamps, when powered
below their rated current and voltage,
can provide extremely long and reliable
operation.
A 3-position header connector, labeled P12,
is located on the Model 210’s main printed
circuit board. It provides access to, and a
means to power, the two lamps. Contact
the factory for details on implementation.
Remote Control Connections
Provision has been made on the Model
210’s printed circuit board assembly to allow external switches or contact closures to
control the main output and talkback output
functions. A 3-position header, labeled P14,
provides access to the circuitry associated with the functions. Pin 1 of the header
is connected to the common point of the
Model 210’s circuitry. Pin 2 of the header
is connected to the circuitry associated with
main output pushbutton. Pin 3 of the header is connected to the circuitry associated
with the talkback output pushbutton.
The input circuitry is “active low,” with a
10 k ohm resistor connected to +5 volts
acting as a pull up. A combination of resistors and capacitors provide ESD protection.
A qualified technician can use these inputs
for special applications. Contact the factory
for additional details.
Model 210 User Guide Issue 5, September 2012
Studio Technologies, Inc. Page 33
Compressor Circuit
In this section some general information
about the Model 210’s compressor
circuit will be provided. As previously
discussed, the output of the microphone
preamplifier circuit is connected to a
studio-quality compressor circuit. The output of the compressor is used by the talkback output and, if configured, the main
output. (In most cases the main output
will utilize the signal coming directly out
of the microphone preamplifier.) The gain
element in the compressor circuit is a
laser-trimmed voltage-controlledamplifier integrated circuit. It provides
accurate, low-noise, low-distortion performance. The threshold of the compressor circuit is 2 dB above the Model 210’s
nominal internal operating level of –2 dBu.
A 5:1 compression ratio is implemented
and, like the threshold level, is not field
adjustable. The threshold and ratio settings were selected so that excellent
talkback audio would be provided. By
controlling the dynamic range, intelligibility
can be improved and overloading of connected devices can be avoided. An LED
indicator lights whenever the compressor’s threshold has been reached and the
circuit is actively controlling the dynamic
range. This LED is provided as an aid
when setting the gain of the microphone
preamplifier.
Issue 5, September 2012 Model 210 User Guide
Page 34 Studio Technologies, Inc.
Specifications
General Audio:
Frequency Response:
mic in/main out
Distortion (THD+N): 0.008%, measured at 1 kHz,
mic in/main out
S/N Ratio: 80 dB, referenced to –46 dBu mic in/
–2 dBu main out
Connectors:
Mic In, IFB In: 3-pin female XLR
Main Out, Talkback Out:
Headphone Out: ¼-inch 3-conductor phone jack
24 Vdc Power In:
locking bushing, compatible with Switchcraft S760K
plug
Spare Connector Locations: 2
Allows one or two Neutrik NC*D-L-1 connectors to
be installed (*=3F, 3M, 5F, 5M, 6F, 6FS, etc.)
Microphone Input/Preamplifier:
Type:
electronically balanced
Input Impedance: 2 k ohms, nominal
Gain Range: 20 to 60 dB, nominal, adjustable in
10 dB steps; 0 dB (no gain) also available
Compatibility: dynamic or phantom-powered mics
Phantom Power:
IEC 61938 P48 standard
IFB Input:
Type:
2-channel, unbalanced (pin 1 common;
pin 2 DC with channel 1 audio; pin 3 channel 2
audio). Also compatible with “dry” audio signals
with signal levels of less than 0 dBu.
Impedance: 10 k ohms, nominal
Nominal Level: –10 dBu
Optional Line Inputs: 2
Implementation: one or two line input cards (Studio
Technologies part number 31084) can be installed
into back panel
Type:
balanced, transformer-coupled
Impedance: 10 k ohms, nominal
Nominal Level: +4 dBu
20 Hz-20 kHz, ±0.1 dB,
3-pin male XLR
coaxial power jack, 2.1 x 5.5 mm,
48 volts DC, nominal, meets
Compressor:
Threshold: 2 dB above nominal level
Attack/Release Time:
Slope: 5:1, nominal
Status LED: compressor active
Main Output:
Type: balanced, transformer-coupled
Nominal Level: –2 dBu
Maximum Level: +20 dBu into 2 k ohms
Impedance: 100 ohms, nominal
Talkback Output:
Type: transformer-coupled with series capacitors
and isolation resistors
Impedance: 600 ohms, nominal
Nominal Level: +4 dBu
Maximum Level: +11 dBu (compressor restricts
maximum)
Headphone Output: 1, stereo
Compatibility: intended for connection to mono
or stereo headphones or headsets with nominal
impedance of 100 ohms or greater
Type:
voltage driver
Maximum Output Voltage:
Relay Contact:
Function
talkback output
Type: form-A (normally open, not-shorted) solid-
state relay contact
Rating: 100 mA, 60 volts AC/DC, maximum
Contact Resistance: 16 ohms, maximum
Access: requires user-implemented connection
method
Power Sources:
IFB: 24-32 volts DC, 105 mA
External: 24 volts DC nominal, 70 mA @ 24 volts
DC; acceptable range 20-30 volts DC. Units ship
with 24 volt DC output power supply.
Dimensions (Overall):
5.6 inches wide (14.2 cm)
3.3 inches high (8.4 cm)
8.5 inches deep (22.4 cm)
: configurable, follows status of main or
2 mSec/100 mSec, nominal
13 Vpp, 150 ohm load
Weight: 3.4 pounds (1.6 kg)
Specifications and information contained in this
User Guide subject to change without notice.
Model 210 User Guide Issue 5, September 2012
Studio Technologies, Inc. Page 35
Appendix A
Attached to the bottom of the unit is a security plate with text that provides a summary
of the configurable parameters and related information.
Issue 5, September 2012 Model 210 User Guide
Page 36 Studio Technologies, Inc.
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