Manual

Model 5401A User Guide Issue 2, July 2021
Studio Technologies, Inc. Page 19
5401A’s sync input and is serving as the
unit’s timing reference. If Locked (Standby)
is displayed this indicates that a valid sig-
nal is connected to the Model 5401A’s sync
input and while it is capable of serving as
the unit’s main timing reference it is not cur-
rently serving as the main clock source.
If Unlocked is displayed it can be the re-
sult of several conditions. It can display if
a signal is connected to the Model 5401A’s
sync input but is not being recognized as
a valid timing reference. This can occur for
multiple reasons. The most common would
be due to a configuration mismatch, such as
if a video reference is connected while the
Model 5401A’s sync input is configured to
support a word clock source. It might also
indicate that a non-supported word clock
rate or an incompatible video reference is
connected. Unlocked could also be dis-
played if no signal is connected to the sync
input or if a connected signal is incorrectly
terminated, e.g., no termination applied
when one is required or if two terminations
(“a double termination”) were present.
Idle will display if the sync input has not
been selected as the Model 5401A’s main
clock source and a valid source has not
been connected to the sync input. It simply
indicates that the sync input circuitry is not
actively receiving an external signal.
Primary Leader Clock: A display-only field
will show the MAC (media access control)
address of the Dante network’s currently
active Primary Leader Clock. Displayed to
the right of the MAC address will be an ad-
ditional piece of information about what spe-
cific device is associated with the displayed
MAC address. If the MAC address is asso-
ciated with this specific Model 5401A then
the text will show (This Device). If the MAC
address is not for this specific Model 5401A
the text will show (Other Device).
A logical question to ask would be “so what
is this Other Device?” Unfortunately, the
Model 5401A’s firmware does not have
the ability to know more about a specific
Primary Leader Clock other than its MAC
address. It can only determine if the MAC
address matches this specific Model 5401A
or not. If the address doesn’t match then
another device has to be serving as the
Primary Leader. The Dante Controller may
provide more detailed information about a
Dante network’s clocking. And network soft-
ware or hardware tools may allow a MAC
address to be associated with a specific
device.
Note that the information provided in this
field can be a bit confusing, even to the
writer of this guide. But for a network maven
it can be very useful when troubleshooting
a complex network timing issue. Reviewing
several related issues to Primary Leader
Clock can be valuable. First of all, it’s impor-
tant to note that the reference to the word
primary in “Primary Leader Clock” has noth-
ing to do with the primary and secondary
Ethernet interfaces! In this context Primary
Leader Clock refers to the device that all
other devices in a Dante network will follow.
In most cases, a Model 5401A will serve
as the Primary Leader Clock. But there is
no requirement that it must play this role.
For example, a Model 5401A can serve as
a Leader Clock while following the timing
provided by another device that’s serving
as the Primary Leader Clock. For another
example, one Model 5401A could serve as
the Primary Leader Clock while several oth-
er Model 5401A units serve as PTP bound-
ary clocks. These boundary clocks would,
by way of a unicast PTP message, synchro-
nize with the Primary Leader Clock. The
boundary clocks could then provide PTPv1
and PTPv2 functionality (using multicast)
with timing based on that derived from the
Primary Leader Clock. This method may be