Studio Technologies 5401A User manual

50701-0721, Issue 2
Copyright © 2021 by Studio Technologies, Inc., all rights reserved
studio-tech.com
User Guide
Issue 2, July 2021
This User Guide is applicable for serial numbers
M5401A-01001 and later with Main MCU Firmware 1.04 and later
Model 5401A
Dante® Leader Clock

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Model 5401A User Guide Issue 2, July 2021
Studio Technologies, Inc. Page 3
Table of Contents
Revision History ................................................................................................................. 4
Introduction ......................................................................................................................... 5
Installation .......................................................................................................................... 9
Dante Configuration ........................................................................................................... 12
Model 5401A Configuration ................................................................................................ 15
Operation ............................................................................................................................ 29
Technical Notes .................................................................................................................. 40
Specifications ..................................................................................................................... 45
Appendix A–Compatible Sync Input Sources ..................................................................... 47
Appendix B–Network Configuration Examples ................................................................... 48
Appendix C–Dante Controller Network Default Configuration Values ................................ 51
Appendix D–Menu Structure .............................................................................................. 52
Appendix E–Screen Captures ............................................................................................ 53
Appendix F–Model 5401A Default Configuration Values .................................................... 58
Appendix G–PTPv2 (IEEE® 1588-2008) Default Characteristics ...................................... 59
Appendix H–Accessing the Unit when User Name and/or Password are Not Known ....... 60

Issue 2, July 2021 Model 5401A User Guide
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Revision History
Issue 2, July 2021:
• Documents support for 176.4 and 192 kHz sample rates.
• Miscellaneous corrections and clarifications.
Issue 1, May 2021:
• Initial release.

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Studio Technologies, Inc. Page 5
Introduction
The Model 5401A Dante Leader Clock pro-
vides precise timing signals for applications
that utilize the Dante audio-over-IP media
networking technology. The unit implements
a high-performance IEEE® 1588 precision
time protocol (PTP) server, compatible with
the requirements of Dante and capable of
simultaneously supporting the timing needs
of up to hundreds of Dante-compatible
devices. As expected, the Model 5401A
provides the PTPv1 (IEEE 1588-2002)
compatibility that’s required by Dante.
In addition, the unit supports PTPv2 (IEEE
1588-2008) for AES67 applications. A word
clock output provides a general-purpose
timing reference for use by external devic-
es. The Model 5401A also generates eight
sine wave audio tones on Dante transmit-
ter (output) channels which can be useful
during audio and data network installation,
maintenance, and operation. A sync input
connection allows the Model 5401A’s in-
ternal oscillator to be synchronized with a
variety of timing and reference signals.
The Model 5401A is suitable for use in fixed
and mobile broadcast facilities, post-pro-
duction studios, commercial and education-
al theater environments, and entertainment
applications. Only power and one, two, or
three Ethernet network connections are
required for full operation. Using Dante’s
inherent capabilities two Model 5401A units
can serve in primary and backup Leader
clock roles for redundant operation.
The unit’s three Gigabit Ethernet (GigE)
network interfaces can be configured for
use in a range of network implementations.
For high-reliability audio applications two
of the interfaces can support Dante redun-
dancy operation while the third is used for
accessing the management webpages. To
meet the latest interoperability standard the
Model 5401A’s Dante implementation sup-
ports AES67-2018. The unit also integrates
with the Dante Domain Manager™ (DDM)
software application.
An integrated web server allows fast and
flexible monitoring and configuration of
the unit’s networking, clocking, and Dante
performance. Front-panel LED indicators,
an LCD display, and pushbutton switches
provide users with direct access to key
operating parameters.
The Model 5401A can be powered by 100-
240 V, 50/60 Hz mains or a source of 12
volts DC. Both can be simultaneously con-
nected to provide redundant operation. The
lightweight enclosure mounts in one space
(1U) of a 19-inch equipment rack. Industry-
standard connectors are used for Ethernet,
DC power, and AC mains interconnections.
Updating the Model 5401A’s operating
software can be easily performed using a
standard USB flash drive.
Figure 1. Model 5401A Dante Leader Clock front and back views

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Applications
Applications for the Model 5401A include
broadcast and post-production facilities,
college and university audio networks, are-
nas, stadiums, corporate installations, and
virtually any application where substantial
numbers of Dante-compatible devices are
utilized. The Model 5401A will serve as a
stable and consistent Leader clock for the
entire Dante “network.” And, as expected,
the Model 5401A is compatible with all
Dante devices, no matter what their function
or manufacturer. Applications that utilize
devices compatible with AES67 will also
benefit from the Model 5401A’s resources.
Why a Dedicated Dante
Leader Clock?
With Dante ubiquitous in fixed and mobile
facilities of all sizes and types, the need
arose for a cost-effective, purpose-
designed, dedicated Leader clock. While
an inherent strength of Dante networking
is its carefully implemented use of the IEEE
1588 standard to ensure that all connected
devices maintain a common timing refer-
ence, the actual performance can vary
widely depending on the specific Dante
devices in use and the overall number of
devices on a network. There are many
Dante-compatible devices that can provide
adequate basic performance as a Leader
clock, but with the Model 5401A networked
audio systems get the benefits of a high-
performance Primary Leader Clock, along
with additional unique capabilities. The
unit’s feature set, along with the associ-
ated internal hardware and software, was
designed to provide optimum performance,
flexibility, and system integrity.
Timing Sources
The Model 5401A can provide excellent
Leader clock performance using its tem-
perature- stabilized internal oscillator, which
exceeds the capability of standard Dante
devices by at least an order of magnitude.
While its standalone performance is excel-
lent, the Model 5401A can also be “locked”
to a variety of external signals for integra-
tion into facilities that include a central or
main timing reference. Compatible signals
include word clock, video reference, and
10 MHz.
Word clock is a square wave signal that is
often used as a timing reference in audio-
only facilities. Several common word clock
rates, including 48, 96 kHz, and the more-
exotic 192 kHz, are compatible with the
Model 5401A’s sync input. Video reference
(“sync”) signals are found in most broadcast
and post-production facilities. The Model
5401A supports the most-common video
format/rate combinations including “black
burst,” bi- and tri-level HD, and several that
are specifically intended for 4K applications.
Industrial and commercial facilities often uti-
lize a GPS-disciplined source of 10 MHz as
a timing reference. This sine wave signal is
typically compatible with the Model 5401A’s
sync input.
Word Clock Output
The Model 5401A generates a precise word
clock output signal that can be used as a
timing reference for related equipment. It’s
specifically intended for “locking” digital
audio devices in applications that use the
Model 5401A to provide timing reference
signals for the associated Dante equipment.
In this way, all devices in an installation will
share a common timing reference.
The word clock output rate can be 44.1, 48,
88.2, 96, 176.4, or 192 kHz. The underlying
timing source for the word clock output is
derived from the Model 5401A’s main timing
source. As previously reviewed, the internal
oscillator, if desired, can be “locked” to an
external source. The main timing source
is divided and processed by the Model

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Studio Technologies, Inc. Page 7
5401A’s logic circuitry to create the highly
stable word clock output. This ensures that
the word clock output is synchronized with
the unit’s PTPv1 and PTPv2 server func-
tionality.
Audio Tone Generator
The Model 5401A generates eight sine
wave audio tones intended for general-pur-
pose use. These audio tones are available
from the Model 5401A by way of Dante
transmitter (output) channels and can be
connected, using the Dante Controller ap-
plication, to Dante receivers (inputs) on
related equipment. The flexibility of being
able to interconnect signals (create Dante
“subscriptions”) between all Dante devices
on a network allows the audio tones to be
used for a variety of purposes. Configura-
tion choices allow the frequency and level
of each sine wave tone to be optimized for
use in specific applications.
Leader Clock Support for
Dante Networks
A core part of the technology underlying
Dante audio-over-IP networking ensures
that all connected devices follow a com-
mon timing reference. This is accomplished
using the PTPv1 (IEEE 1588-2002) and
PTPv2 (IEEE 1588-2008) precision time
protocols. Any connected Dante device
can be used as a Leader clock; there is no
requirement that a dedicated Leader clock
device be utilized to realize adequate func-
tionality. However, the actual performance
can vary widely depending on the specific
Dante devices available and the overall
number of Dante devices on a network.
Many Dante devices utilize the 2- or 4-
channel Ultimo™ ULT or UXT integrated
circuits to implement Dante connectiv-
ity. While Ultimo devices will fully support
Dante audio transport, they are not well
suited to serve as a Leader clock. Ultimo’s
PTP performance is limited and does not
have the ability to synchronize with an
external timing reference. Other Dante
devices may use the Brooklyn II module
or Broadway integrated circuit to support
Dante connectivity. In some cases, these
devices can provide good basic perfor-
mance as a Leader clock.
However, problems and limitations may
arise when these devices are called upon
to perform “double duty,” serving in both a
primary function (such as analog-to-Dante
interfacing or audio signal processing) as
well as acting as a Leader clock. This is un-
derstandable as the main purpose of these
devices is to serve functions other than act-
ing as a primary synchronization reference.
Timing related features, such as allowing
connection of a video bi- or tri-level sync
signal is rarely, if ever, supported. And PTP
performance can degrade when the com-
puting power of a device is intended pri-
marily for handling and manipulating digital
audio signals. This can lead to the required
PTP resources being in short supply when
the number of Dante devices that need
timing messages moves into the hundreds.
Also, firmware updates, cabling changes,
and other maintenance tasks typically asso-
ciated with a general-purpose Dante device
would impact the Leader clock functionality
for an entire installation.
The Model 5401A was specifically designed
to support a Dante-based audio system’s
Leader clock requirement. And the unit’s
generation of audio tones and implementa-
tion of the word clock output utilize hard-
ware circuitry that is separate from that
associated with its PTP functionality. As
such, this secondary functionality will not
interfere with PTP operation. Unlike a
general-purpose Dante device, once mount-
ed in an equipment rack and the required

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interconnections are made, the Model
5401A will perform its tasks without risk
of interruption due to conflicting resource
demands.
Flexible Networking
Capability
Using the Dante Controller application
program, the Model 5401A’s three Eth-
ernet ports can be selected to operate in
one of four modes: Switched, Redundant,
Switched+Mgmt, and Redundant+Mgmt.
This should allow virtually any desired
networking implementation to be easily
achieved.
By using the Switched or Redundant net-
work modes, separate network connections
will be maintained for Dante audio and
management purposes.
In the Switched mode a single Ethernet
connection to either of the Model 5401A’s
two Dante Ethernet ports will provide Dante
Leader clock functionality. The remain-
ing Dante Ethernet port will provide Dante
network “loop-through” capability and can
be used to interface with another piece
of Ethernet-connected equipment. The
management Ethernet port will be used to
access the Model 5401A’s monitoring and
configuration webpages.
In the Redundant mode two independent
Ethernet connections are made to the
Model 5401A’s two Dante Ethernet ports,
enabling Dante’s redundant networking
capability. Again, the management Ether-
net port will be used to access the Model
5401A’s monitoring and configuration
webpages.
In the Switched+Mgmt mode a single Ether-
net connection is used for both Dante Lead-
er clock functionality as well as providing
access to the Model 5401A’s management
webpages. The remaining Dante Ethernet
port will provide network “loop-through”
capability and can be used to interface
with another piece of Ethernet-connected
equipment.
In the Redundant+Mgmt mode two inde-
pendent Ethernet connections can be made
to the Model 5401A’s two Dante Ethernet
ports. This will enable Leader clock ca-
pability for applications that utilize Dante
redundancy. Access to the Model 5401A’s
management webpages will be made by
way of the Ethernet connection made to the
Dante primary Ethernet port.
Operating Power
The Model 5401A allows an AC mains
source of 100-240 V, 50/60 Hz to be directly
connected. It can also be DC powered us-
ing a 10-18 volt source that is connected via
a broadcast-standard 4-pin XLR connector.
If both AC and DC power sources are con-
nected the unit will be powered by the AC
mains supply. Only if the AC mains source
fails will appreciable power be drawn from
the DC source. This allows a source of DC,
typically an external power supply, to serve
in a backup capacity. With this arrangement
normal operation can continue even if AC
mains power is lost.
Future Capabilities
The Model 5401A was designed so that its
capabilities can be enhanced in the future.
A USB receptacle located on the unit’s
back panel, allows the three firmware files
(embedded software) to be updated us-
ing a USB flash drive. The Model 5401A’s
Dante firmware can be updated using one
of the unit’s Ethernet connections, helping
to ensure that the Dante capabilities remain
up to date. All software files and configura-
tion parameters are stored in non-volatile
memory.

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Installation
In this section the Model 5401A will be
mounted in one space (1U) of an equipment
rack. In many cases, an external synchroni-
zation source will be connected to the sync
input BNC jack. If needed, a connection may
be made to the word clock output BNC jack
on the back panel. One or more Ethernet
data connections will be made. AC mains
and/or DC power will be connected to the
Model 5401A.
Using a coaxial cable terminated with a BNC
plug, an external source of synchronization
may be connected to the sync input. A word
clock output is provided by way of a BNC
jack and may be utilized by one or more
pieces of equipment. Up to three Ethernet
data connections will be made to the Model
5401A using standard RJ45 patch cables.
AC mains power can be connected to the
Model 5401A by means of a detachable cord
that is compatible with the unit’s 3-pin IEC
320 C14 inlet connector. Some applications
may warrant connection to a source of nomi-
nal 12 volts DC which can be made by way
of a 4-pin XLR connector. A DC source can
be used to power the Model 5401A as well
as serving as a backup power source should
AC mains not be present.
What’s Included
The shipping carton contains a Model 5401A
Dante Leader Clock and instructions on how
to obtain an electronic copy of this guide.
Also included in the shipping carton is a
North-American-standard AC mains cord.
For destinations outside of North America
the local reseller or distributor should pro-
vide an appropriate AC mains cord.
Mounting the Model 5401A
The Model 5401A Dante Leader Clock re-
quires one space (1U) in a standard 19-inch
(48.3 cm) equipment rack. Secure the unit
into the designated equipment rack using
two mounting screws per side. As the Mod-
el 5401A does not contain a fan or other
noise-producing source it can be located
within a room or other structure where au-
dio monitoring is going to take place. Some
or all of the connections involving the sync
input BNC jack, the word clock output BNC
jack, the Ethernet interface RJ45 jacks, and
the AC mains and/or DC power connectors
may be utilized.
Twisted-pair (UTC) Ethernet has a 100-
meter (325-foot) interconnection cable limi-
tation. But that can be overcome by using
fiber-optic interconnections between the
Model 5401A and the Ethernet switch or
switches in the one or more associated
local-area-networks (LANs).
Sync Input
An external synchronization source can be
connected to the Model 5401A’s sync input
BNC jack. Located on the back panel, this
input allows the Model 5401A’s internal tim-
ing to be “locked” to an external reference.
Signals that are compatible with the Model
5401A’s sync input include word clock, bi-
level video, tri-level video, and 10 MHz sine
wave. A configuration setting in the Sync
Input webpage defines what type of signal
is going to be connected. Another setting
defines if a termination impedance is ap-
plied to the sync input. Refer to the Specifi-
cations section of this guide for the general
characteristics required of acceptable exter-
nal sync signals.
A connected word clock signal must be a
square wave with a rate that matches the
Dante sample rate as defined in the Dante
Controller application. The rate can be 44.1,
48, 88.2, 96, 176.4, or 192 kHz. If termina-
tion has been enabled for the sync input
when it has been configured for word clock
an impedance of 75 ohms will be applied.

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A source of bi-level or tri-level video can
also be connected to the sync input. Circuit-
ry within the Model 5401A will decode many
of the common video rates and formats, al-
lowing them to serve as a timing reference.
Refer to Appendix A, located at the end of
this guide, for a list of compatible rates and
formats. If the sync input is configured for
video and termination has been enabled an
impedance of 75 ohms will be applied.
A source of 10 MHz sine wave can be con-
nected to the Model 5401A’s sync input.
This type of signal is commonly used as
a timing reference in industrial and instru-
mentation applications. An impedance of 50
ohms will be applied to the sync input if ter-
mination has been enabled and the source
is selected for 10 MHz.
Word Clock Output
A word clock output signal is provided for
use by other devices that want to be “timed”
from the Model 5401A. Available by way
of a BNC jack located on the back panel,
the square wave output has a frequency
that matches the unit’s configured Dante
sample rate. Choices are 44.1, 48, 88.2, 96,
176.4, and 192 kHz. The exact frequency
of the word clock output is based on the
timing reference that has been selected for
the Model 5401A. If, for example, the Sync
Input was selected as the unit’s timing refer-
ence, then the word clock output would be
“locked” to it.
The source impedance of the word clock
signal is 75 ohms and its unterminated
output level is 5 volts peak-to-peak (Vpp).
When externally terminated with a 75 ohm
load the word clock output level will drop to
2.5 Vpp.
Ethernet Connections
The Model 5401A provides three Giga-
bit Ethernet (GigE) ports for flexibility and
compatibility with many networking imple-
mentations. Two ports are provided for
interconnections with one or two local area
networks (LANs) associated with Dante
audio-over-IP networking schemes. They
are labeled as PRI (primary) and SEC (sec-
ondary). The third Ethernet port, labeled
MGMT, can be used to access the Model
5401A management resources. An internal
web server function supports the Model
5401A’s management port’s webpages.
These webpages are used for configura-
tion, monitoring, and maintenance of Model
5401A operation. Refer to Figure 2 for an
overview of the Model 5401A’s three Ether-
net ports and how they can operate.
Using the Dante Controller application,
the three Ethernet ports can be config-
ured to operate in one of four modes:
Switched, Redundant, Switched+Mgmt, or
Redundant+Mgmt. If configured for either
the Switched or Redundant modes the
management webpages are accessed by
way of the management Ethernet port.
When configured for the Switched+Mgmt
mode the management webpages are
accessed by way of either the primary or
secondary Ethernet ports. When configured
for the Redundant+Mgmt mode the man-
agement webpages are accessed using an
Ethernet connection made to the primary
Ethernet port.
By providing three Ethernet ports and four
configuration modes, the Model 5401A al-
lows support for virtually all facilities, includ-
ing those that utilize separate networks for
Dante audio transport and equipment man-
agement. In this way, “production” networks
that support transport of audio signals by
way of a single LAN (Switched mode) or
two LANs (Redundant mode) can be sepa-
rate from an engineering network that is
used by technical personnel for configuring
and maintaining a facility or “plant.”