Studio Technologies 5421 Users Guide

Model 5421

Dante Intercom Audio Engine

User Guide

Issue 2, September 2022

This User Guide is applicable for serial numbers

M5421-00151 and later with Main Firmware version 1.03 and later,

FPGA Firmware version 1.01 and later,

and STcontroller application version 3.09.03 and later.

Copyright © 2022 by Studio Technologies, Inc., all rights reserved

studio-tech.com

50671-0922 Issue 2

This page intentionally left blank.

Table of Contents

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

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

Getting Started .............................................................. 7

Dante Conguration....................................................... 9

Model 5421 Conguration ............................................. 11

Operation ...................................................................... 14

Technical Notes ............................................................ 15

Specications ............................................................... 19

Appendix A.................................................................... 20

Appendix B ................................................................... 21

Appendix C ................................................................... 22

Model 5421 User Guide Issue 2, September 2022
Studio Technologies, Inc. Page 3

Revision History

Issue 2, September 2022:

• Updated for clarity.

Issue 1, March 2020:

• Initial release of complete document.

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Introduction

The Model 5421 Dante® Intercom Audio

Engine is a high-performance, cost-e󰀨ective,
exible 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 xed and mobile broadcast facili­ties, post-production studios, commercial and
educational theater environments, and enter­tainment 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 Tech­nologies’ STcontroller software application

allows personnel to view and congure 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 in­teroperability 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 congured to pro­vide from one to four “virtual” intercom circuits.
The term “audio engine” was selected to de­scribe a set of audio input, processing, routing,

and output resources that can be congured to
support specic 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.

Conguration and Functionality

Using the STcontroller software application a

conguration choice selects how the Model

5421’s 16-channel audio engine is segmented.

The allows e󰀩cient use of the Dante channels
to support the needs of specic 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 dened and an
appropriate conguration be made.

The 16 channels o󰀨ered by the Model 5421
are congured into what are called groups.
Simple conguration choices are accessed

using the STcontroller software application
and allow the number of groups and their

sizes to be selected. Group conguration can
range from one group having 16 channels (a

complete audio engine being used for a single
group) to four groups each having four chan­nels. 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 congurations 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 reect how each spe­cic group is going to be utilized. Names such
as Production, Lighting, Stage Manager, or

Follow Spot would be typically used in theater­oriented intercom applications.

Technically, each group supports party-line
operation by creating a series of unique “mix­minus” outputs, one for each channel in the
group. These specialized outputs allow each

intercom user assigned to that specic 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 Tech­nologies. 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-sup­porting 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-over­Ethernet 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-

gured to support, or not support, AES67 digital

audio signals. The unit is also compliant with the

Dante Domain Manager (DDM) software appli­cation. DDM o󰀨ers 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 ap­plications, far exceeding that of “typical” intercom
products. Audio processing is performed in the

digital domain using a high-speed eld-program­mable-gate-array (FPGA) integrated circuit.

Issue 2, September 2022 Model 5421 User Guide
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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 o󰀨ers the opportunity for users to obtain
the absolutely nest audio performance.

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.

Status LEDs and Conguration

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 conguration switches are provided. The

Studio Technologies’ STcontroller software
application is used to congure 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 man­agement 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, light­weight aluminum enclosure that is designed to

be “eld 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 at 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

Future Capabilities and Firmware
Updating

The Model 5421 was designed so that its per­formance and capabilities can be enhanced
in the future. A USB type A connector, acces­sible on the unit’s back panel, allows the main

rmware (embedded software) to be updated
using a standard USB ash drive. To imple-

ment its Dante interface the Model 5421 uses
Audinate’s Broadway™ integrated circuit. The
rmware in this integrated circuit can be up­dated 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 19­inch equipment rack then an optional rack-

mount installation kit is required. Specic 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 (325­foot) twisted pair Ethernet cable limitation. But

the overall length limit can be overcome by
using a ber-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 ber

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 bot­tom 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-over­Ethernet (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 func­tionality 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 cross­over or “reversing” cable is not required. And

while “Fast Ethernet” (100BASE-TX or 100 Mb)

may also function correctly, it’s not recom­mended 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 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 thread­pitch 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 ngers to rotate them counter­clockwise; no tool is required. It’s probably a
good idea to store the four “bump on” protec­tors 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 enclo­sure, 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 re­moved and the standard and long rack brack­ets have been installed the Model 5421 will
be 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 unit into the equip­ment 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 thread­pitch Phillips-head machine screws, and two
2-56 thread-pitch Torx T7 thread-forming ma­chine 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 n­gers to rotate them counterclockwise; no tool
is required. Store the eight “bump on” protec­tors 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 nal 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 rst

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 t 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 Conguration

For audio to correctly pass to and from the
Model 5421 requires that, at a minimum, sev-

eral Dante-related parameters be congured.
These conguration settings will be stored in

non-volatile memory within the Model 5421’s

circuitry. Conguration will typically be done

with the Dante Controller software application
which is available for download free of charge
at audinate.com. Versions of Dante Controller

are available to support Windows and OS X®

operating systems. The Model 5421 uses
the Broadway integrated circuit to implement
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 su󰀩x.

The su󰀩x identies the specic Model 5421
that is being congured. The su󰀩x’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 Con­troller application, the default device name and
channel names can be revised as appropriate

for the specic application.

Sample Rate, Encoding, Clocking,

& Latency

The Model 5421 only supports an audio
sample rate of 48 kHz with no pull-up/pull­down 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 Conguration –
Addresses

By default, the Model 5421’s Dante IP address
and related network parameters will be deter­mined 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 xed (static) conguration. While this

is a more-involved process than simply let-

ting DHCP or link-local “do their thing,” if xed

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 “con-

sole tape,” noting its specic 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 for additional details.

AES67 Conguration – AES67 Mode

Using Dante Controller, the Model 5421 can be

congured for AES67 operation. This requires
that the AES67 Mode conguration choice to

be set for Enabled. By default, the Model 5421

has this mode congured 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 re­ceive “sync” from another device that’s been
selected as the “primary leader” for the appli­cation. 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) out­put 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 (sub­scribed) 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 conguration

error occurs when the transmitter/receiver pair
is not correctly routed: as a pair, to the same

specic 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 problem if
channels are left as “spares” for future use. It is
important to always remember that channels in
a group always consist of a transmitter/receiver
pair.

Flows

The number of receiver ows associated with

the Model 5421’s Broadway integrated circuit is

16. The same applies to the number of trans-

mitter ows. Each ow can either be unicast,

multicast, or a combination of the two. No

receiver ow limitation will ever exist as there’s
one ow available for each of the 16 receiver
channels. In most cases, 16 transmitter ows
should prevent an issue of insu󰀩cient 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 “subscrip­tion” is the term used for routing a transmitter

ow (a group of output channels) to a receiver
ow (a group of input channels).

Model 5421 Conguration

The Studio Technologies’ STcontroller software
application is used to congure the way in

which the Model 5421 functions. No web
pages or physical switch settings are used to
congure 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 (studio-tech.com/
stcontroller-application/) and is compatible with
personal computers running Windows operat-

ing systems that are version 7 and later.
STcontroller versions 2.06.00 and later are
required to fully support the Model 5421. If re­quired, download and install STcontroller onto
a designated personal computer. This person­al computer must be on the same local area

network (LAN) and subnet as the Model 5421
unit that is to be congured. 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 congured will appear in the device list. Use

the Identify command to allow easy recognition

of a specic Model 5421 unit. Double-clicking

on a device name will cause the associated

conguration menu to appear. Review the cur­rent conguration and make any changes that
are desired. The Save Conguration and Load
Conguration functions allow specic proles

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 conguration choices

available for all compatible Studio Technolo­gies’ products. The demo mode also provides

the ability to create and save conguration
proles without requiring the actual units to be
present. These saved conguration proles

can then be loaded into actual units when they
become available on the related network.

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Congurable Parameters

The Model 5421 allows conguration of two functions. They are:

• System – Channels Per Group

• System – Auto Mix

Changes made using STcontroller will be immediately reected 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 ash orange four times to indicate that a command from STcontroller has been

received.

The following two sections provide details on

the congurable parameters.

of four channels each. As should be evident,
adding together the size of each group will

always equal 16. What conguration choice is

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
congured to function in one of ve available
group arrangements. These groups dene

the maximum number of Dante device talk/
listen channels that can join together to form

a virtual party-line (PL). The conguration

choices range from 16 which creates one

large (16-channel) PL to selecting 4, 4, 4, 4
which creates four independent PL groups

Issue 2, September 2022 Model 5421 User Guide
Page 12 Studio Technologies, Inc.

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 conguration.

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 pro­cessing is performed within the digital do-

main.) 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 conrmation 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

dened by the group size, this does not mean

that all channels associated with a group
have to be utilized. For example, if the Mod-

el 5421 is congured to provide two groups
of eight channels, the rst group could have
ve 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 denes the

maximum 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 se­lected then a maximum number of 16 of talk/
listen channels from Dante-compatible devic-

es 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 to work together to sup­port two independent channels, then a Model

5421 conguration choice of 8, 8 would be

appropriate.

When contemplating changing the group
conguration it’s important to note two things.
The rst is that Dante channel names may
automatically change to reect the revised
group conguration. 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 conguration has been selected and
conrmed. 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 destruc­tive as far as channel names and routes are

concerned. A change of group conguration

is “one way”; there’s no method to go back to

a previous group conguration and have the

channel names and routes be automatically
re-established.

System – Auto Mix

Choices are O 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 au­tomatically adjust the contribution that each
input signals makes to the group. This auto­matic mixing action will perform two tasks.
It will help balance the audio level of each

input that has a signicant 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 xed threshold. This helps ensure

Model 5421 User Guide Issue 2, September 2022
Studio Technologies, Inc. Page 13

that users who are actively talking on a PL

circuit 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 o󰀨 the Auto Mix function. Refer

to the Technical Notes section 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 conguration param­eters should have been reviewed and selected
as desired. The Dante Controller software ap­plication allowed the network-related congura­tion 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 desired party-line intercom virtual
circuits.

Initial Operation

Typically, a Model 5421 will begin functioning
within approximately 30 seconds of its Pow-

er-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 ash

whenever Ethernet data is passing through
the interface.

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 ash once. In addition,
the two bi-color LEDs on front panel, labeled
SYS and SYNC, will rst 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 associ­ated Dante network. Both the SYS and SYNC
LEDs will light red when their associated func­tions 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 useful
during operation and troubleshooting. The
SYNC LED will light red when the Ethernet
interface is not synchronized with the Dante
network. It will light solid green when the Ether­net interface is fully synchronized with the con­nected Dante network and an external clock

source (timing reference) is being received.
The SYNC LED will slowly ash green if the

Model 5421’s Dante interface is serving as the
leader clock for the connected Dante network.

How to Identify a Specic
Model 5421

The Dante Controller and STcontroller software

applications o󰀨er an Identify command that can
be used to help locate a specic Model 5421
device. When the Identify command is selected
the SYS and SYNC LEDs on the front panel
will ash. After a few seconds the identication

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 nd 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.

Issue 2, September 2022 Model 5421 User Guide
Page 14 Studio Technologies, Inc.

It will slowly ash green if the unit is serving

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 mainte­nance is required.

The STcontroller application is used to make

any required conguration changes. It can
also be used to nd detailed information
about the Model 5421’s rmware (embedded
software) and Dante interface. Application
rmware updates will be made using the USB

connector on the back panel. Dante interface

rmware updates will be performed using the
Ethernet connection. Details regarding rm-

ware updates are provided later in this guide.

Technical Notes

Users who are familiar with the Studio Tech­nologies’ Model 5422 Dante Intercom Audio
Engine may recall that each of the unit’s

groups can be independently congured 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, o󰀨ers only intercom groups. But sim­ply 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 su󰀩cient 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.

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. (Re­member, the Model 5421 creates mix-minus
buses; each output has everything but its as-

sociated input!) In practice this means that by
selecting di󰀨erent group size congurations

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.

IP Address Assignment

By default, the Model 5421’s Ethernet inter­face will attempt to automatically obtain an
IP address and associated settings using

DHCP (Dynamic Host Conguration Pro­tocol). If a DHCP server is not detected an

IP address will automatically be assigned
using the link-local protocol. This protocol is
known in the Microsoft® world as Automat-

ic Private IP Addressing (APIPA). It is also
sometimes referred to as auto-IP (PIPPA).
Link-local will randomly assign a unique IP

address in the IPv4 range of 169.254.0.1 to

169.254.255.254. In this way, multiple Dan­te-enabled devices can be connected togeth­er and automatically function, whether or not

a DHCP server is active on the LAN. Even

two Dante-enabled devices that are directly
interconnected using an RJ45 patch cord
should correctly acquire IP addresses and be
able to communicate with each other.

Model 5421 User Guide Issue 2, September 2022
Studio Technologies, Inc. Page 15

As previously discussed, the Model 5421’s
Dante IP address and related network param-

eters can be manually set for a xed (static)
conguration using the Dante Controller soft-

ware application. In the unfortunate event that

a specic Model 5421’s IP address is “lost”

there are several techniques that may prove
useful. It’s possible that the Address Resolu-

tion Protocol (ARP) networking command can

be used to “probe” devices on a network for

this information. For example, in Windows OS

the arp –a command can be used to display

a list of LAN information that includes MAC

addresses and corresponding IP addresses.

(Within this list should be the Model 5421’s
statically assigned Dante IP address.) This
method is most e󰀨ective with a LAN that uses

unmanaged Ethernet switches. Contemporary

LANs that utilize managed switches may limit
the ARP command’s e󰀨ectiveness.

In general, the simplest means of identifying
an unknown IP address is to create a “mini”
LAN with an unmanaged PoE-enabled Ether­net 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 addition­al piece of equipment required would be a PoE
mid-span power supply for providing 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 perfor­mance a network that supports VoIP QoS

(voice-over-internet-protocol quality of service)

capability is recommended. This can typically
be implemented on virtually all contemporary
managed Ethernet switches. There are even
specialized switches that are optimized for en­tertainment-associated applications. Refer

to the Audinate website (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 Mod-

el 5421’s two rmware (embedded software)
components. These are the application rm­ware and the FPGA rmware. The application
rmware is used by the unit’s microcontroller

integrated circuit to implement the Model 5421’s

general operating actions. The FPGA rmware
is used by the eld-programmable-gate-array

integrated circuit which performs all audio pro­cessing functions.

To observe the rmware version numbers,

begin by connecting the Model 5421’s Ethernet
port to a network. The unit will begin to func­tion approximately 30 seconds after power is
supplied. Start STcontroller, review the list of

identied devices, and select the specic Model
5421 from which you want to determine its rm-

ware 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 rmware versions as well as details
on the Dante interface rmware.

Application Firmware Update

Procedure

It’s possible that updated versions of the two

rmware (embedded software) les that are

utilized by the Model 5421’s microcontroller and
FPGA (eld-programmable-gate-array) integrat­ed circuit will be released to add features or cor­rect issues. Refer to the Studio Technologies’

website for the latest rmware les. The unit
has the ability to load revised les into non-vol­atile memory by way of a standard USB ash

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

Issue 2, September 2022 Model 5421 User Guide
Page 16 Studio Technologies, Inc.

Model 5421 updates its rmware using les

named M5421.bin for the main rmware and
BWYA.bit for the FPGA rmware.

The update process begins by preparing a

USB ash drive. The ash drive doesn’t
have to be empty (blank) but must be in the

personal-computer-standard FAT32 format.
One or both of the rmware les can be
automatically loaded and will be done sequen­tially. In the root directory save the desired

new rmware le(s), ensuring that the required
name or names are specied. For the
application rmware the le name must be
M5421.bin and for the FPGA rmware the le

name must be BWYA.bit. Studio Technologies

will supply each rmware le inside a .zip
archive le. While the rmware le inside of
the zip le will adhere to the naming convention

required by the Model 5421, the name of

the zip le itself will include the le’s ver­sion number. For example, a le named

M5421v1r00MCU.zip would indicate that

version 1.00 of the application rmware
(M5421.bin) is contained within this zip le.

Once the USB ash drive is inserted into the

USB type A receptacle, located on the back

panel, the unit must be powered o󰀨 and then
powered on again. At this point the le(s) will

automatically load. The precise steps required
will be highlighted in the next paragraphs.

To install either or both of the rmware les
follow these steps:

1. Remove power from the Model 5421 by
disconnecting the Ethernet connection from
the RJ45 jack on the back panel.

2. Locate the USB type A connector on the

Model 5421’s back panel, labeled Firmware
Update. Directly to the right of the USB con­nector is a small hole that provides visual

access to a green LED indicator.

3. Insert the prepared USB ash drive into

the USB connector.

4. Apply power to the Model 5421 by recon­necting 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

rmware le(s) that are present on the
USB ash drive. The update process can

range from approximately 15 seconds to
approximately 45 seconds, depending on

which les are going to be updated. While
the les are being loaded the green LED,

located to the right of the USB connector,

will ash slowly. Once the loading process

has completed the Model 5421 will restart

using the newly saved main rmware.

6. At this time the Model 5421 is functioning

with the newly loaded rmware and the
USB ash drive can be removed. But to

be conservative, remove the power source

rst and then remove the USB ash drive.

7. If necessary, restart the Model 5421 by
connecting the Ethernet with PoE signal

to the RJ45 jack. Conrm that the desired
rmware has been loaded and that the
Model 5421’s two rmware les 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 ash drive doesn’t
have the correct le(s) in its root folder no

harm will occur. Upon power up the green

LED, located below the USB connector, will
ash on and o󰀨 rapidly for a few seconds to
indicate that a valid le has not been found.

After this indicating sequence has completed
then normal operation using the unit’s existing

application and FPGA rmware will begin.

Model 5421 User Guide Issue 2, September 2022
Studio Technologies, Inc. Page 17

Broadway Firmware Update

As previously discussed, the Model 5421
implements Dante connectivity using the
Broadway integrated circuit from Audinate. The
STcontroller software application can be used

to identify the Dante rmware version. (Use the
Version selection under the Device tab.)

The rmware (embedded software) residing

in Broadway can be updated using the Model
5421’s Ethernet port. Performing the update
process is easily accomplished using an au­tomated method called Dante Updater that’s
included as part of the Dante Controller ap­plication. This application is available, free of

charge, from the Audinate website (audinate.
com). The latest Model 5421 rmware le, with

a name in the form of M5421vXrXrX.dnt, is
always available on the Studio Technologies’
website as well as being part of Audinate’s
product library database. The latter allows the
Dante Updater software application that is
included with Dante Controller to automatically
query and, if required, update the Model 5421’s
Dante interface.

Restoring Factory Defaults

A command in the STcontroller software appli-

cation allows the Model 5421’s conguration

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

Issue 2, September 2022 Model 5421 User Guide
Page 18 Studio Technologies, Inc.

Specications

Applications:

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, xed
Input-to-Output Audio Processing Latency: <100 uSec
Auto Mix: sophisticated FPGA-based algorithm provides

enhanced party-line (PL) audio intelligibility (selectable
on or o󰀨)

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

Conguration: requires Studio Technologies’
STcontroller software application, version 2.06.00 and
later

designed to create from one to four virtual

Connectors:

Ethernet: 1, RJ45

USB: type A receptacle (used only for updating applica­tion and FPGA rmware)

Software Updating: USB ash drive used for updating
application and FPGA rmware; Dante Controller

or Dante Firmware Update Manager applications can

be used for updating Dante interface rmware

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 dual­unit (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)

Specications and information contained in this

User Guide subject to change without notice.

Model 5421 User Guide Issue 2, September 2022
Studio Technologies, Inc. Page 19

Appendix A–Example of Model 5421 Routes (Subscriptions) made using
Dante Controller

Issue 2, September 2022 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)

Model 5421 User Guide Issue 2, September 2022
Studio Technologies, Inc. Page 21

Appendix C–Graphical Description of Rack-Mount Installation Kit
for Two Model 5421 Units (Order Code: RMBK-12)

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).

Issue 2, September 2022 Model 5421 User Guide
Page 22 Studio Technologies, Inc.