Studio Technologies 5421 User manual

Copyright © 2020 by Studio Technologies, Inc., all rights reserved
www.studio-tech.com
User Guide
Issue 1, March 2020
This User Guide is applicable for serial numbers
M5421-00151 and later with main firmware version 1.00 and later
and STcontroller application version 2.06.00 and later.
50671-0320 Issue 1
Model 5421
Dante® Intercom Audio Engine

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Model 5421 User Guide Issue 1, March 2020
Studio Technologies, Inc. Page 3
Table of Contents
Revision History ........................................................... 4
Introduction .................................................................... 5
Getting Started .............................................................. 7
Dante Configuration ...................................................... 9
Model 5421 Configuration ............................................. 11
Operation ...................................................................... 13
Technical Notes ............................................................ 14
Specifications ............................................................... 18
Appendix A ................................................................... 19
Appendix B ................................................................... 20
Appendix C ................................................................... 21

Issue 1, March 2020 Model 5421 User Guide
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Revision History
Issue 1, March 2020:
• Initial release of complete document.

Model 5421 User Guide Issue 1, March 2020
Studio Technologies, Inc. Page 5
Introduction
The Model 5421 Dante® Intercom Audio
Engine is a high-performance, cost-effective,
flexible solution for creating party-line (PL)
intercom circuits. It’s directly compatible with
the Studio Technologies’ range of 1-, 2-, and
4-channel Dante-enabled beltpacks and other
interface-related products. The unit is suitable
for use in fixed and mobile broadcast facili-
ties, post-production studios, commercial and
educational theater environments, and enter-
tainment applications.
Only a Gigabit Ethernet network connection
with Power-over-Ethernet (PoE) support is
required for the Model 5421 to provide a
powerful resource in a variety of Dante appli-
cations. Front- and back-panel LEDs provide
operating status indications. The Studio Tech-
nologies’ STcontroller software application
allows personnel to view and configure key
operating parameters. The unit’s lightweight
“1/2-rack” enclosure can be used stand-alone
or mounted in one space (1U) of a standard
19-inch rack enclosure with an optional rack-
mount installation kit. To meet the latest in-
teroperability standard the Model 5421’s Dante
implementation meets the requirements of
AES67 as well as supporting the Dante Do-
main Manager (DDM) application. Using DDM,
compliance with ST 2110-30 may be possible.
The Model 5421 provides one 16-channel
audio engine which can be configured to pro-
vide from one to four “virtual” intercom circuits.
The term “audio engine” was selected to de-
scribe a set of audio input, processing, routing,
and output resources that can be configured to
support specific intercom requirements. Unlike
general-purpose Dante digital matrix devices,
the Model 5421 is optimized to allow direct
support for theater, small broadcast, and
general intercom applications.
Configuration and Functionality
Using the STcontroller software application a
configuration choice selects how the Model
5421’s 16-channel audio engine is segmented.
The allows efficient use of the Dante channels
to support the needs of specific applications.
As all Dante intercom beltpacks are essentially
Figure 1. Model 5421 Dante Intercom Audio Engine “throw down” front view
Figure 2. Model 5421 Dante Intercom Audio Engine back view

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4-wire devices (having independent receiver
(input) and transmitter (output) channels)
“virtual” (simulated) party-line functional-
ity must be created within the Model 5421’s
digital processing resources. This requires that
the maximum number of participants (users)
on any one “party-line” be defined and an
appropriate configuration be made.
The 16 channels offered by the Model 5421
are configured into what are called groups.
Simple configuration choices are accessed
using the STcontroller software application
and allow the number of groups and their
sizes to be selected. Group configuration can
range from one group having 16 channels (a
complete audio engine being used for a single
group) to four groups each having four chan-
nels. The size of a group will dictate how many
devices and associated users can be part of
any one party-line. Five choices allow a range
of group configurations to be selected with the
default setting being two 8-channel groups.
Using the Dante Controller application, each
group can be assigned a unique name. These
names would typically reflect how each spe-
cific group is going to be utilized. Names such
as Production, Lighting, Stage Manager, or
Follow Spot would be typically used in theater-
oriented intercom applications.
Technically, each group supports party-line
operation by creating a series of unique “mix-
minus” outputs, one for each channel in the
group. These specialized outputs allow each
intercom user assigned to that specific group
(a “party-line”) to hear all members of that
group except for themselves. (Thus comes
the term “mix-minus” or a mix of all source
but themselves.) By each user receiving a
mix-minus signal precise control of each
user’s local sidetone audio level and overall
audio quality can be maintained.
Applications
The Model 5421 is compatible with many
Dante-compliant devices including the extensive
range of intercom beltpacks from Studio Tech-
nologies. These include the single-channel/
dual-listen Model 372A and Model 373A, the
2-channel Model 370A and Model 371A, and
the 4-channel Model 374A. The Model 5421
will also function directly with other Dante-sup-
porting devices such as the Model 348 Intercom
Station and Model 391 Dante Alerting Unit. In
addition, the Model 5421 can function with matrix
intercom systems, audio consoles, and wireless
intercom base stations.
Dante Audio-over-Ethernet
Audio data associated with the Model 5421 is
sent and received using the Dante audio-over-
Ethernet media networking technology. Audio
signals with a sample rate of 48 kHz and a bit
depth of up to 16, 24, and 32 are supported. Up
to 16 Dante receiver (input) and 16 transmitter
(output) channels are available to implement
virtual party-line (PL) intercom circuits.
AES67 and DDM
Using the Dante Controller software application,
the Model 5421’s Dante interface can be con-
figured to support, or not support, AES67 digital
audio signals. The unit is also compliant with the
Dante Domain Manager (DDM) software appli-
cation. DDM offers an enhanced set of network
control and monitoring features, making it ideal
for security-conscious applications. This may
also allow the Model 5421’s audio channels to
support ST 2110-30.
Pro Audio Quality and Auto Mix
The Model 5421’s audio circuitry was designed
to meet the demands of professional audio ap-
plications, far exceeding that of “typical” intercom
products. Audio processing is performed in the
digital domain using a high-speed field-program-
mable-gate-array (FPGA) integrated circuit.

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The Model 5421’s Auto Mix function utilizes a
sophisticated FPGA-based algorithm to provide
enhanced audio intelligibility. This feature is
unique to party-line (PL) intercom applications
and offers the opportunity for users to obtain
the absolutely finest audio performance.
Status LEDs and Configuration
Two LEDs, located on the Model 5421’s front
panel, provide an indication of the Dante inter-
face’s status. LEDs associated with the back-
panel R45 jack display the real-time status of
the connected Ethernet signal. No pushbutton
or configuration switches are provided. The
Studio Technologies’ STcontroller software
application is used to configure the unit’s
operating parameters.
Ethernet Data and Power Source
The Model 5421 interconnects with a local-
area-network (LAN) using a standard Gigabit
(1000 Mb/s) twisted-pair Ethernet signal. The
physical connection is made by way of a RJ45
receptacle. The Model 5421’s operating power
is provided by a Power-over-Ethernet (PoE)-
compliant Ethernet signal. For network man-
agement purposes the unit’s Ethernet interface
will report to the power sourcing equipment
(PSE) that it’s a class 2 (low power) powered
device (PD).
Simple Installation
The Model 5421 is housed in a rugged, light-
weight aluminum enclosure that is designed to
be “field tough.” It can be used as a standalone
portable unit, supporting what’s known in the
broadcast world as “throw-down” applications.
Or it also can be directly placed upon on a
rack-shelf or other flat surface. Optional rack-
mount installation kits are available to allow
one or two units to be mounted in one space
(1U) of a standard 19-inch rack enclosure. As
previously mentioned, the Model 5421 uses
a standard RJ45 connector to allow fast and
convenient interconnection. Initial operation
will commence when a Gigabit Ethernet signal
with Power-over-Ethernet (PoE) capability is
connected. Normal operation will take place
after the unit “boots up.” This process requires
approximately 30 seconds.
Future Capabilities and Firmware
Updating
The Model 5421 was designed so that its per-
formance and capabilities can be enhanced
in the future. A USB type A connector, acces-
sible on the unit’s back panel, allows the main
firmware (embedded software) to be updated
using a standard USB flash drive. To imple-
ment its Dante interface the Model 5421 uses
Audinate’s Broadway™ integrated circuit. The
firmware in this integrated circuit can be up-
dated via the unit’s Ethernet interface, helping
to ensure that the Dante performance remains
up to date.
Getting Started
In this section a location will be selected for
the Model 5421 Dante Intercom Engine. A
Gigabit Ethernet (GigE or GbE) connection
that supports Power-over-Ethernet (PoE) will
be made using a standard RJ45 patch cable.
If desired, an optional rack-mount installation
kit will be used to mount one or two Model
5421 units into a standard equipment rack.
System Components
Included in the shipping carton are a Model
5421 Dante Intercom Audio Engine and a
printed copy of this guide. If one or two Model
5421 units are going to be mounted in a 19-
inch equipment rack then an optional rack-
mount installation kit is required. Specific kits
are available for rack-mounting one or two
Model 5421 units. If a rack-mount installation
kit was purchased it would typically have been
shipped in a separate carton.

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Locating the Model 5421
The location of the Model 5421 will primarily
depend on being within the 100-meter (325-
foot) twisted pair Ethernet cable limitation. But
the overall length limit can be overcome by
using a fiber-optic interconnection between
the Model 5421-related Ethernet switch and
another Ethernet switch that’s part of the ap-
plication’s local-area-network (LAN). With fiber
interconnects there’s no reason why a Dante-
supported LAN can’t be distributed over many
miles or kilometers.
Protecting the Enclosure
The Model 5421 is shipped as a self-contained
unit suitable for portable use or placement in a
semi-permanent location. Installed on the bot-
tom of the chassis are screw-on “bump on”
protectors (also known as rubber “feet”). These
are useful if the unit is going to be placed on
surfaces where scratching of either the Model
5421’s enclosure or the surface material could
take place. However, if applicable the “feet”
can be removed without the use of a tool, when
rack- or custom-mounting the unit.
Making an Ethernet Connection
The Model 5421 has one RJ45 jack which is
located on the unit’s back panel. It requires
connection with a Gigabit Ethernet (GigE or
GbE) signal that also supports Power-over-
Ethernet (PoE). This is typically provided by
a port on a standard PoE-enabled Gigabit
Ethernet switch. The required Gigabit Ethernet
signal must follow the 1000BASE-T standard
and meet the requirements of IEEE® 802.3af
for PoE. To support power management func-
tionality on the associated PoE switch (PSE)
the Model 5421 enumerates itself as a PoE
class 2 (low power) powered device (PD).
The Model 5421’s Ethernet interface supports
auto MDI/MDI-X and, as such, using a cross-
over or “reversing” cable is not required. And
while “Fast Ethernet” (100BASE-TX or 100 Mb)
may also function correctly, it’s not recom-
mended for maximum reliability.
Rack Mounting
For some applications it might be desirable to
mount one or two Model 5421 units into one
space (1U) of a 19-inch rack enclosure. Rack-
mount installation kits, purchased separately,
are available from Studio Technologies. The
following sections provide details on how to
use the rack-mount kits. Refer to Appendices B
and C of this guide for graphical descriptions of
how to attach the rack-mount kits.
Rack-Mounting One Model 5421 Unit
Rack-mount installation kit RMBK-11 is used
to allow rack mounting of one Model 5421 unit.
The kit contains one standard rack bracket,
one long rack bracket, and four 6-32 thread-
pitch Phillips-head machine screws. Refer to
Appendix B for a visual explanation.
Begin the installation by removing the four
“bump on” protectors from the bottom of the
Model 5421’s chassis. They can be removed
using one’s fingers to rotate them counter-
clockwise; no tool is required. It’s probably a
good idea to store the four “bump on” protec-
tors for possible later use.
With assistance from a #2 Phillips-tip screw
driver, use the machine screws to attach the
standard and long rack brackets to the sides
of the Model 5421’s enclosure. The screws will
mate with the threaded fasteners that can be
seen on the sides of the Model 5421’s enclo-
sure, near the front of the unit.
Mount the standard rack bracket to the left
side of the Model 5421 (when viewed from the
front) if the unit needs to be located on the left
side of the rack enclosure. Then mount the
long rack bracket to the right side of the Model
5421. Mount the brackets in the opposite
orientation should the Model 5421 need to be
located on the right side of the rack enclosure.

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Once the “bump on” protectors have been re-
moved and the standard and long rack brack-
ets have been installed the Model 5421 will
be ready to be mounted into the designated
equipment rack. One space (1U or 1.75 verti-
cal inches) in a standard 19-inch equipment
rack is required. Secure the unit into the equip-
ment rack using two mounting screws per side.
Rack-Mounting Two Model 5421 Units
Rack-mount installation kit RMBK-12 is used
to allow one-space (1U) rack mounting of two
Model 5421 units. The kit can also be used to
mount one Model 5421 and another product
that is compatible with the RMBK-12 (such as
the Studio Technologies’ Model 48D Dante
Bridge). The kit contains two standard rack
brackets, two joiner plates, eight 6-32 thread-
pitch Phillips-head machine screws, and two
2-56 thread-pitch Torx T7 thread-forming ma-
chine screws. Refer to Appendix C for a visual
explanation.
Begin installing the kit by removing the four
“bump on” protectors from the bottom of each
chassis. They can be removed using one’s fin-
gers to rotate them counterclockwise; no tool
is required. Store the eight “bump on” protec-
tors for possible later use.
With assistance from a #2 Phillips-tip screw
driver, use two of the 6-32 machine screws to
attach one of the standard rack brackets to the
left side (when viewed from the front) of one
of the Model 5421 units. The screws will mate
with the threaded fasteners that can be seen
on the sides of the Model 5421’s enclosure,
near the front of the unit. Using two more of
the 6-32 machine screws, attach one of the
joiner plates to the right side of that same
Model 5421 unit.
Again using two of the 6-32 machine screws,
attach the second standard rack bracket to
the right side of the second Model 5421 or
other compatible unit. Using the final two 6-32
machine screws, attach the second joiner plate
to the left side of the second Model 5421 or
other compatible unit with an orientation of
180 degrees from the way in which the first
plate was installed.
To complete the assembly, “join” the units
together by sliding each joiner plate through
the other. The grooves in each joiner plate will
carefully align with each other and form a rela-
tively tight bond. Line up the two units so that
the front panels form a common plane. With
the aid of a Torx T7 driver, use the two 2-56
machine screws to secure the two joiner plates
together. The screws should fit snugly into the
small openings formed by the mating of the
two joiner plates.
Once the “bump on” protectors are removed
and the 2-unit assembly is created it is ready
to be mounted into the designated equipment
rack. One space (1U or 1.75 vertical inches) in
a standard 19-inch equipment rack is required.
Secure the assembly into the equipment rack
using two mounting screws per side.
Dante Configuration
For audio to correctly pass to and from the
Model 5421 requires that, at a minimum, sev-
eral Dante-related parameters be configured.
These configuration settings will be stored in
non-volatile memory within the Model 5421’s
circuitry. Configuration will typically be done
with the Dante Controller software application
which is available for download free of charge
at www.audinate.com. Versions of Dante Con-
troller are available to support Windows and
OS X® operating systems. The Model 5421
uses the Broadway integrated circuit to imple-
ment the Dante functionality. The Model 5421
is compatible with the Dante Domain Manager
(DDM) software application. This may allow
ST 2110-30 routes to be established to and
from the Model 5421’s audio channels.

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Unit and Channel Names
The Model 5421 has a default Dante device
name of ST-M5421- along with a unique suffix.
The suffix identifies the specific Model 5421
that is being configured. The suffix’s actual
alpha and/or numeric characters relate to the
MAC address of the unit’s Broadway integrated
circuit. By default, the 16 Dante receiver (Rx)
and 16 Dante transmitter (Tx) audio channels
are organized as two 8-channel groups. The
channel default names are A01-Group A
through A08-Group A and B01-Group B
through B08-Group B. Using the Dante Con-
troller application, the default device name and
channel names can be revised as appropriate
for the specific application.
Sample Rate, Encoding, Clocking,
& Latency
The Model 5421 only supports an audio
sample rate of 48 kHz with no pull-up/pull-
down values available. Encoding choices are
PCM 24, PCM 16, and PCM 32, but in virtually
all cases the default selection of PCM 24 would
be appropriate. This is due to the processing
within the Model 5421 being performed in
24-bit. Device Latency can be adjusted if
required but the default value of 1.0 msec
will typically be correct.
Network Configuration –
Addresses
By default, the Model 5421’s Dante IP address
and related network parameters will be deter-
mined automatically using the DHCP protocol
or, if not available as a network resource, the
link-local protocol. If desired, Dante Controller
allows the Model 5421’s IP address and related
network parameters to be manually set to a
fixed (static) configuration. While this is a more-
involved process than simply letting DHCP or
link-local “do their thing,” if fixed addressing is
necessary then this capability is available. But
in this case, it’s highly recommended that a
unit be physically marked, e.g., directly using a
permanent marker and “console tape,” noting
its specific static IP address. If knowledge of a
Model 5421’s IP address has been misplaced
there is no reset button or other simple method
to identify and restore the unit to a default IP
setting. Refer to the Technical Notes section of
this guide for additional details.
AES67 Configuration – AES67 Mode
Using Dante Controller, the Model 5421 can be
configured for AES67 operation. This requires
that the AES67 Mode configuration choice to
be set for Enabled. By default, the Model 5421
has this mode configured for Disabled.
Clocking
As is the case for all Dante devices, the Model
5421 can serve as a leader clock for a Dante
network. But in many cases, the unit will re-
ceive “sync” from another device that’s been
selected as the “primary leader” for the ap-
plication. As such, the check box for Preferred
Leader associated with the Model 5421 would
typically not be enabled. But for supporting a
small to medium sized set of Dante devices
there’s no reason why the Model 5421 couldn’t
perform admirably as a leader clock. In this
case checking the box for Preferred Leader
would be appropriate.
Audio Routing
Each Model 5421 Dante transmitter (Tx) out-
put channel associated with a channel in an
intercom group must be routed (subscribed) to
the desired receiver channel on an associated
piece of equipment. The receiver (Rx) input
associated with the same channel in the same
intercom group must also be routed (sub-
scribed) to that same piece of equipment. One
transmitter channel and one receiver channel
always create a transmitter/receiver pair that is
used as one channel in a party-line (PL) group.

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Refer to Appendix A for an example of Model
5421 routes (subscriptions) made using Dante
Controller.
The most common Model 5421 configuration
error occurs when the transmitter/receiver pair
is not correctly routed: as a pair, to the same
specific device and channel on the device. An
intercom user device, such as a beltpack from
Studio Technologies, must have a talk and
listen channel from the same channel routed
to the same channel on the same intercom
group from the Model 5421.
It’s not necessary to route signals to and from
all transmitter and receiver channels on a
Model 5421 intercom group. There’s no prob-
lem if channels are left as “spares” for future
use. It is important to always remember that
channels in a group always consist of a trans-
mitter/receiver pair.
Flows
The number of receiver flows associated with
the Model 5421’s Broadway integrated cir-
cuit is 16. The same applies to the number
of transmitter flows. Each flow can either be
unicast, multicast, or a combination of the
two. No receiver flow limitation will ever ex-
ist as there’s one flow available for each of
the 16 receiver channels. In most cases, 16
transmitter flows should prevent an issue of
insufficient transmitter from occurring. When
a Model 5421 is operating in the AES67 mode
the transmitter (output) channels will always
function in multicast. In AES67 unicast is not
supported.
Note that within Dante Controller a “subscrip-
tion” is the term used for routing a transmitter
flow (a group of output channels) to a receiver
flow (a group of input channels).
Model 5421 Configuration
The Studio Technologies’ STcontroller soft-
ware application is used to configure the way
in which the Model 5421 functions. No web
pages or physical switch settings are used to
configure the unit. This makes it imperative that
STcontroller be available for convenient use on
a personal computer that’s connected to the
related LAN.
Installing STcontroller
STcontroller is available free of charge on the
Studio Technologies’ website (www.studio-tech.
com/stcontroller-application/) and is compat-
ible with personal computers running Windows
operating systems that are version 7 and later.
STcontroller versions 2.06.00 and later are
required to fully support the Model 5421. If re-
quired, download and install STcontroller onto
a designated personal computer. This personal
computer must be on the same local area
network (LAN) and subnet as the Model 5421
unit that is to be configured. Immediately after
starting STcontroller the application will locate
all the Studio Technologies’ devices that it can
control. The one or more Model 5421 units to
be configured will appear in the device list. Use
the Identify command to allow easy recognition
of a specific Model 5421 unit. Double-clicking
on a device name will cause the associated
configuration menu to appear. Review the cur-
rent configuration and make any changes that
are desired. The Save Configuration and Load
Configuration functions allow specific profiles
to be saved and then loaded into one or more
units as necessary.
Using STcontroller’s demo mode is an easy
means of reviewing the configuration choices
available for all compatible Studio Technolo-
gies’ products. The demo mode also provides
the ability to create and save configuration
profiles without requiring the actual units to be
present. These saved configuration profiles

Issue 1, March 2020 Model 5421 User Guide
Page 12 Studio Technologies, Inc.
can then be loaded into actual units when
they become available on the related network.
Configurable Parameters
The Model 5421 allows configuration of two
functions. They are:
• System – Channels Per Group
• System – Auto Mix
Changes made using STcontroller will be im-
mediately reflected in the unit’s operation; no
Model 5421 reboot is required. Each time a
change is made the two LEDs on the Model
5421’s front panel will flash orange four times
to indicate that a command from STcontroller
has been received.
The following two sections provide details on
the configurable parameters.
System – Channels Per Group
Choices are 16; 12, 4; 8, 8; 8, 4, 4; and
4, 4, 4, 4.
The Model 5421’s 16 Dante receiver (input)
and 16 transmitter (output) channels can be
configured to function in one of five avail-
able group arrangements. These groups
define the maximum number of Dante device
talk/listen channels that can join together to
form a virtual party-line (PL). The configura-
tion choices range from 16 which creates one
large (16-channel) PL to selecting 4, 4, 4, 4
which creates four independent PL groups
of four channels each. As should be evident,
adding together the size of each group will
always equal 16. What configuration choice is
optimal for an application will depend on the
maximum number of independent PL “circuits”
that need to be established. A simple review
of an application should lead to the desired
group configuration.
Inside the Model 5421 each group is isolated
from each other, ensuring that there is no
audio crosstalk. (This is to be expected as all
Model 5421 audio inputs, outputs, and pro-
cessing is performed within the digital domain.)
Each member of a group is assigned its own
mix-minus channel, meaning that the audio
that it supplies to the group is routed to all
other members of the group but not to itself.
A user receives confirmation audio from their
own microphone by way of its local sidetone
function and not from the group’s mixing and
distribution functions that create the multiple
mix-minus buses.
While the maximum number of talk/listen
channels that can be assigned to a group is
defined by the group size, this does not mean
that all channels associated with a group have
to be utilized. For example, if the Model 5421
is configured to provide two groups of eight
channels, the first group could have five talk/
listen channels routed to it while the second
group could have just three talk/listen channels
routed to it. The unused channels in a group
don’t contribute any noise or audio artifacts.
They are simply “spare” and available for
future use. They allow additional talk/listen
channels to be routed to them as needed.
Groups are just resources that allow talk/listen
channels on compatible devices to be linked
together. A group size just defines the maxi-
mum number of device channels that can be
part of a set of users that can talk and listen
among themselves.
As an example, if a group size of 16 is select-
ed then a maximum number of 16 of talk/listen
channels from Dante-compatible devices can
be assigned (routed to or subscribed) to the
group. This would equate to up to 16 of the
Studio Technologies’ Model 372A or Model
373A single-talk channel beltpacks being able
to function together in what to user’s would
be a party-line (PL) or shared communication
channel or circuit. If, as another example, an
application required that eight of the 2-channel
Model 370A or Model 371A beltpacks needed

Model 5421 User Guide Issue 1, March 2020
Studio Technologies, Inc. Page 13
to work together to support two independent
channels, then a Model 5421 configuration
choice of 8, 8 would be appropriate.
When contemplating changing the group
configuration it’s important to note two things.
The first is that Dante channel names may
automatically change to reflect the revised
group configuration. This is not necessarily a
terrible thing but some re-editing of channel
names may be required to achieve the desire
implementation.
The second issue that could arise is that
some or all existing Dante audio channel
routes (subscriptions) may be removed upon
a change in the group size. In this case, they
will have to be re-established once the new
group configuration has been selected and
confirmed. Again, this is not a terrible thing
to have occur. But it’s possible that up to 32
Dante routes (subscriptions), consisting of
16 receiver/transmitter pairs, may have to
be re-established.
In conclusion, these changes may be destruc-
tive as far as channel names and routes are
concerned. A change of group configuration
is “one way”; there’s no method to go back to
a previous group configuration and have the
channel names and routes be automatically
re-established.
System – Auto Mix
Choices are Off and On.
A special audio processing algorithm can
be enabled to allow enhanced audio perfor-
mance for party-line (PL) applications. This
algorithm, implemented in the high-speed
logic of the FPGA integrated circuit, will au-
tomatically adjust the contribution that each
input signals makes to the group. This auto-
matic mixing action will perform two tasks.
It will help balance the audio level of each
input that has a significant signal presented
to its associated input. It will also reduce the
contribution to the overall mix that each input
signal will present if its level is determined to
be below a fixed threshold. This helps ensure
that users who are actively talking on a PL cir-
cuit will be clearly heard while those who are
not actively talking will have their background
audio minimized.
In most cases leaving Auto Mix enabled will
be appropriate. Special applications, such
as using groups as unity gain digital mixers,
may warrant turning off the Auto Mix func-
tion. Refer to the Technical Notes section in
this guide for details on how a group could be
used for a mixing, rather than in an intercom
(PL), application.
Operation
At this point the Model 5421 should have a
GigE PoE Ethernet connection made to the
network interface jack. Using the STcontroller
software application, the configuration pa-
rameters should have been reviewed and
selected as desired. The Dante Controller
software application allowed the network-
related configuration settings to have been
made. This included enabling AES67 support
if needed. The Dante output (transmitter) and
input (receiver) channel pairs should have
been routed (subscribed) to create the de-
sired party-line intercom virtual circuits.
Initial Operation
Typically, a Model 5421 will begin functioning
within approximately 30 seconds of its Power-
over-Ethernet (PoE) power source being
connected. The two status LEDs that are part
of the RJ45 jack have the names LINK and
ACT. The LINK LED is orange and will light
when a network connection has been estab-
lished. The ACT LED is green and will flash
whenever Ethernet data is passing through
the interface.

Issue 1, March 2020 Model 5421 User Guide
Page 14 Studio Technologies, Inc.
Upon power being connected the Model 5421’s
microprocessor will start to function and initi-
ate an LED test sequence. This will cause the
green LED associated with the USB connector
on the back panel to flash once. In addition,
the two bi-color LEDs on front panel, labeled
SYS and SYNC, will first light green, then light
red, to indicate that they are functional. After a
few more seconds they will commence normal
operation, reporting on the status of the associ-
ated Dante network. Both the SYS and SYNC
LEDs will light red when their associated func-
tions are not operational.
Dante Status LEDs
On the front panel the user is presented with
two status LEDs. These resources are simple
to understand and should prove to be use-
ful during operation and troubleshooting. The
SYNC LED will light red when the Ethernet in-
terface is not synchronized with the Dante net-
work. It will light solid green when the Ethernet
interface is fully synchronized with the connect-
ed Dante network and an external clock source
(timing reference) is being received. The SYNC
LED will slowly flash green if the Model 5421’s
Dante interface is serving as the leader clock
for the connected Dante network.
How to Identify a Specific
Model 5421
The Dante Controller and STcontroller software
applications offer an Identify command that can
be used to help locate a specific Model 5421
device. When the Identify command is selected
the SYS and SYNC LEDs on the front panel
will flash. After a few seconds the identification
patterns will cease and normal Model 5421
LED operation will resume. Audio performance
will not be impacted by the use of the Identify
command. As such, it’s perfectly acceptable to
use this command at any time.
Normal Operation
Normal operation should find the Dante status
LEDs on the front panel lit. SYS should be
solid green. SYNC should be solid green if
an external clock source is providing timing.
It will slowly flash green if the unit is serv-
ing as Dante leader clock. The Model 5421
is designed for continuous operation. It uses
low-power circuitry, consuming about 4 watts
under normal conditions. No regular mainte-
nance is required.
The STcontroller application is used to make
any required configuration changes. It can
also be used to find detailed information
about the Model 5421’s firmware (embedded
software) and Dante interface. Application
firmware updates will be made using the USB
connector on the back panel. Dante interface
firmware updates will be performed using the
Ethernet connection. Details regarding firm-
ware updates are provided later in this User
Guide.
Technical Notes
Using a Group for Digital Mixing
Purposes
A Model 5421 group creates party-line (PL)
circuits which are actually a set of mix-minus
buses, one per group member. Group sizes
can range from four to 16 channels. So, as
an example, a group size of eight will have
eight mix-minus buses. The Model 5421 can
be used as a general-purpose Dante unity-
gain mixing device but with one limitation. The
number of input signals allowed to be routed
to the mix “bus” must be one less than the
size of the group. This is because the group’s
channel used as the mix output must not have
an input signal associated with it. Otherwise
that input won’t be present in the mix. (Re-
member, the Model 5421 creates mix-minus

Model 5421 User Guide Issue 1, March 2020
Studio Technologies, Inc. Page 15
buses; each output has everything but its as-
sociated input!) In practice this means that by
selecting different group size configurations
the Model 5421 can be used as 15-, 11-, 7-,
or 3-channel digital mixers. No input signal can
be assigned to a group’s channel that’s being
used as the output.
Users who are familiar with the Studio Tech-
nologies’ Model 5422 Dante Intercom Audio
Engine may recall that each of the unit’s
groups can be independently configured for a
number of modes including intercom, IFB, and
summing bus. The summing bus mode allows
all channels of a group to be used for a mixing
function. The Model 5421, as a more modest
product, offers only intercom groups. But sim-
ply using one channel of a group as an output
allows a mix function to be established.
Depending on the application the Auto Mix
function may – or may not – be useful. In some
situations, the Auto Mix function will be of
sufficient importance to make it valid to use a
Model 5421 just for this resource. Using it for
general-purpose audio applications, and not
just for intercom, may prove to be valuable.
IP Address Assignment
By default, the Model 5421’s Ethernet inter-
face will attempt to automatically obtain an IP
address and associated settings using DHCP
(Dynamic Host Configuration Protocol). If a
DHCP server is not detected an IP address will
automatically be assigned using the link-local
protocol. This protocol is known in the Micro-
soft® world as Automatic Private IP Address-
ing (APIPA). It is also sometimes referred to
as auto-IP (PIPPA). Link-local will randomly
assign a unique IP address in the IPv4 range
of 169.254.0.1 to 169.254.255.254. In this way,
multiple Dante-enabled devices can be con-
nected together and automatically function,
whether or not a DHCP server is active on the
LAN. Even two Dante-enabled devices that are
directly interconnected using an RJ45 patch
cord should correctly acquire IP addresses
and be able to communicate with each other.
As previously discussed in this guide, the
Model 5421’s Dante IP address and related
network parameters can be manually set for
a fixed (static) configuration using the Dante
Controller software application. In the unfor-
tunate event that a specific Model 5421’s IP
address is “lost” there are several techniques
that may prove useful. It’s possible that the
Address Resolution Protocol (ARP) network-
ing command can be used to “probe” devices
on a network for this information. For ex-
ample, in Windows OS the arp –a command
can be used to display a list of LAN informa-
tion that includes MAC addresses and corre-
sponding IP addresses. (Within this list should
be the Model 5421’s statically assigned Dante
IP address.) This method is most effective
with a LAN that uses unmanaged Ethernet
switches. Contemporary LANs that utilize
managed switches may limit the ARP com-
mand’s effectiveness.
In general, the simplest means of identifying
an unknown IP address is to create a “mini”
LAN with an unmanaged PoE-enabled Eth-
ernet switch. Then by using the appropriate
ARP command the required “clues” can
be obtained. It’s also possible to make an
almost-direct connection between a personal
computer and a Model 5421. The only ad-
ditional piece of equipment required would
be a PoE mid-span power supply for provid-
ing power to the Model 5421. From a data
standpoint this implementation would provide
a direct connection between the two Ethernet
ports.
Optimizing Network Performance
For best Dante audio-over-Ethernet per-
formance a network that supports VoIP
QoS (voice-over-internet-protocol quality

Issue 1, March 2020 Model 5421 User Guide
Page 16 Studio Technologies, Inc.
of service) capability is recommended. This
can typically be implemented on virtually all
contemporary managed Ethernet switches.
There are even specialized switches that are
optimized for entertainment-associated appli-
cations. Refer to the Audinate website (www.
audinate.com) for details on how to optimize
a network for Dante applications.
Application Firmware Version
Display
The STcontroller software application is used
to display the version numbers of the Model
5421’s two firmware (embedded software)
components. These are the application firm-
ware and the FPGA firmware. The application
firmware is used by the unit’s microcontroller
integrated circuit to implement the Model
5421’s general operating actions. The FPGA
firmware is used by the field-programmable-
gate-array integrated circuit which performs
all audio processing functions.
To observe the firmware version numbers,
begin by connecting the Model 5421’s Eth-
ernet port to a network. The unit will begin to
function approximately 30 seconds after power
is supplied. Start STcontroller, review the list
of identified devices, and select the specific
Model 5421 from which you want to determine
its firmware versions. Then select Version
under the Device tab. A dialog will then display
that will provide a host of useful information.
This will include the firmware versions as well
as details on the Dante interface firmware.
Application Firmware Update
Procedure
It’s possible that updated versions of the two
firmware (embedded software) files that are
utilized by the Model 5421’s microcontroller
and FPGA (field-programmable-gate-array) in-
tegrated circuit will be released to add features
or correct issues. Refer to the Studio Tech-
nologies’ website for the latest firmware files.
The unit has the ability to load revised files into
non-volatile memory by way of a standard USB
flash drive. The Model 5421 implements a USB
host function and provides access by way of
a type A receptacle located on the unit’s back
panel. The Model 5421 updates its firmware
using files named M5421.bin for the main firm-
ware and BWYA.bit for the FPGA firmware.
The update process begins by preparing a
USB flash drive. The flash drive doesn’t have
to be empty (blank) but must be in the per-
sonal-computer-standard FAT32 format. One
or both of the firmware files can be automati-
cally loaded and will be done sequentially. In
the root directory save the desired new firm-
ware file(s), ensuring that the required name
or names are specified. For the application
firmware the file name must be M5421.bin
and for the FPGA firmware the file name must
be BWYA.bit. Studio Technologies will sup-
ply each firmware file inside a .zip archive file.
While the firmware file inside of the zip file
will adhere to the naming convention required
by the Model 5421, the name of the zip file
itself will include the file’s version number. For
example, a file named M5421v1r00MCU.zip
would indicate that version 1.00 of the applica-
tion firmware (M5421.bin) is contained within
this zip file.
Once the USB flash drive is inserted into the
USB type A receptacle, located on the back
panel, the unit must be powered off and then
powered on again. At this point the file(s) will
automatically load. The precise steps required
will be highlighted in the next paragraphs of
this guide.
To install either or both of the firmware files fol-
low these steps:
1. Remove power from the Model 5421 by
disconnecting the Ethernet connection from
the RJ45 jack on the back panel.

Model 5421 User Guide Issue 1, March 2020
Studio Technologies, Inc. Page 17
LED, located below the USB connector, will
flash on and off rapidly for a few seconds to
indicate that a valid file has not been found.
After this indicating sequence has completed
then normal operation using the unit’s existing
application and FPGA firmware will begin.
Broadway Firmware Update
As previously discussed in this guide, the
Model 5421 implements Dante connectivity
using the Broadway integrated circuit from
Audinate. The STcontroller software ap-
plication can be used to identify the Dante
firmware version. (Use the Version selection
under the Device tab.) The Dante Controller
software application can also be used to de-
termine the version of the firmware (embed-
ded software) that resides in the Broadway
integrated circuit. Dante Controller also in-
cludes a software update application that can
make updating Broadway firmware a simple
and quick process. Alternately, the Dante
Firmware Update Manager (FUM) application
program can be used to update the Broadway
firmware. Both applications are available,
free of charge, on the Audinate website
(www.audinate.com).
Restoring Factory Defaults
A command in the STcontroller software appli-
cation allows the Model 5421’s configuration
selections to be reset to the factory values.
From STcontroller select the Model 5421 for
which you want to restore its defaults. Select
the Device tab and then select the Factory
Defaults feature. Then click on the OK box.
The two factory default values are:
System – Channels Per Group: 8, 8
System – Auto Mix: On
2. Locate the USB type A connector on the
Model 5421’s back panel, labeled Firm-
ware Update. Directly to the right of the
USB connector is a small hole that pro-
vides visual access to a green LED
indicator.
3. Insert the prepared USB flash drive into
the USB connector.
4. Apply power to the Model 5421 by recon-
necting the Ethernet signal to the RJ45
jack.
5. After a few seconds the Model 5421
will run a “boot loader” program that will
automatically read and then save the new
firmware file(s) that are present on the
USB flash drive. The update process can
range from approximately 15 seconds to
approximately 45 seconds, depending on
which files are going to be updated. While
the files are being loaded the green LED,
located to the right of the USB connector,
will flash slowly. Once the loading process
has completed the Model 5421 will restart
using the newly saved main firmware.
6. At this time the Model 5421 is functioning
with the newly loaded firmware and the
USB flash drive can be removed. But to
be conservative, remove the power source
first and then remove the USB flash drive.
7. If necessary, restart the Model 5421 by
connecting the Ethernet with PoE signal
to the RJ45 jack. Confirm that the desired
firmware has been loaded and that the
Model 5421’s two firmware files are as
desired. This is accomplished using the
STcontroller software application. (Use the
Version selection under the Device tab.)
Note that upon power being applied to the
Model 5421 if the USB flash drive doesn’t
have the correct file(s) in its root folder no
harm will occur. Upon power up the green

Issue 1, March 2020 Model 5421 User Guide
Page 18 Studio Technologies, Inc.
Specifications
Applications: designed to create from one to four virtual
party-line (PL) circuits in Dante audio-over-Ethernet
environments
Engine Group Options:
The following group sizes can be selected:
16 (one group)
12, 4 (two groups)
8, 8 (two groups)
8, 4, 4 (three groups)
4, 4, 4, 4 (four groups)
Audio Performance:
Internal Digital Audio Processing: 24-bit, fixed
Input-to-Output Audio Processing Latency: <100 uSec
Auto Mix: sophisticated FPGA-based algorithm provides
enhanced party-line (PL) audio intelligibility (selectable
on or off)
Network Audio Technology:
Type: Dante audio-over-Ethernet (also known as Dante
audio-over-IP)
AES67-2018 Support: yes
Dante Domain Manager (DDM) Support: yes
Clock Source: Dante network or internal (can serve as
leader clock)
Bit Depth: 16, 24, or 32
Sample Rate: 48 kHz
Number of Dante Receiver (Input) Channels: 16
Number of Dante Transmitter (Output) Channels: 16
Number of Dante Flows: 16 receiver, 16 transmitter
Network Interface:
Type: 1000BASE-T (Gigabit, GigE, or GbE) per IEEE
802.3ab, twisted-pair Ethernet, Power-over-Ethernet
(PoE) supported
Data Rate: 1000 Mb/s (10 Mb/s not supported; 100 Mb/s
supported but not optimal)
Auto MDI/MDI-X Support: yes
NIC Status LEDs: one link and one activity
Power Source:
Power-over-Ethernet (PoE): class 2 (low power,
≤6.49 watts) per IEEE® 802.3af
Configuration: requires Studio Technologies’
STcontroller software application, version 2.06.00 and
later
Connectors:
Ethernet: 1, RJ45
USB: type A receptacle (used only for updating applica-
tion and FPGA firmware)
Software Updating: USB flash drive used for updating
application and FPGA firmware; Dante Controller
or Dante Firmware Update Manager applications can
be used for updating Dante interface firmware
Front Panel LEDs: 2, dual-color
Functions: provides indication of status of Dante
connectivity
Environmental:
Operating Temperature: 0 to 50 degrees C (32 to
122 degrees F)
Storage Temperature: –40 to 70 degrees C (–40 to
158 degrees F)
Humidity: 0 to 95%, non-condensing
Altitude: not characterized
Dimensions – Overall:
8.7 inches wide (22.1 cm)
1.72 inches high (4.4 cm)
8.3 inches deep (21.1 cm)
Mounting Options: single-unit (RMBK-11) and dual-
unit (RMBK-12) rack-mount installation kits, purchased
separately. Each uses one space (1U) in a standard
19-inch rack.
Weight: 1.3 pounds (0.59 kg); rack-mount installation
kits add 0.2 pounds (0.09 kg)
Specifications and information contained in this
User Guide subject to change without notice.

Model 5421 User Guide Issue 1, March 2020
Studio Technologies, Inc. Page 19
Appendix A–Example of Model 5421 Routes (Subscriptions) made using
Dante Controller

Issue 1, March 2020 Model 5421 User Guide
Page 20 Studio Technologies, Inc.
Appendix B–Graphical Description of Rack-Mount Installation Kit
for One Model 5421 Unit (Order Code: RMBK-11)