User Guide
Issue 1, April 2019 Model 373A User Guide
Page 16 Studio Technologies, Inc.
MODEL 373A
INTERCOM BELTPACK
receptacle on the bottom panel, will slowly
flash green. After a few seconds the LED
identification pattern will cease and normal
Model 373A button LED and Dante status
LED operation will resume.
Mic Kill Support
The Model 373A includes a mic kill function,
allowing the talk button, if it has been placed
in its enabled (on) state, to be remotely
forced to its disabled (off) state. This func-
tion is sometimes referred to as a “talk off”
function. Two actions can enable the mic kill
function. Any time a Model 373A receives a
Dante Identify command it will cause both an
LED pattern to start as well as enabling the
mic kill function. The second “trigger” meth-
od uses the Studio Technologies’ Global Mic
Kill command. This command can be acti-
vated from a menu choice in the STcontroller
software application.
The reason for the Model 373A to offer a
mic kill function is simple. It’s common in
intercom applications for users to enable
(“latch on”) a talk channel and then go “off
headset,” forgetting that they’ve left that talk
channel enabled. While they take a break
or go to lunch, all other users are forced
to listen to that channel which may include
unwanted audio. This makes having the abil-
ity to disable a talk channel very useful. The
Dante Identify command allows a “latched
on” talk channel on a specific Model 373A to
be remotely disabled. Alternately, by using
the Global Mic Kill command a large group
of units can simultaneously have their talk
channels disabled. This would include any
Studio Technologies’ compatible device that
follows this protocol.
Technical Notes
IP Address Assignment
By default, the Model 373A’s Ethernet inter-
face will attempt to automatically obtain an
IP address and associated settings using the
DHCP (Dynamic Host Configuration Proto-
col). 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 Automatic Private
IP Addressing (APIPA). It is also sometimes
referred to as auto-IP. Link-local will random-
ly 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 automatical-
ly function, whether or not a DHCP server is
active on the LAN. Even two Dante-enabled
devices that are directly interconnected us-
ing an RJ45 patch cable will, in most cases,
correctly acquire IP addresses and be able
to communicate with each other.
An exception does arise when trying to
directly interconnect two Dante-enabled
devices that use Ultimo integrated circuits
to implement Dante. The Model 373A uses
Ultimo and a design limitation in it prevents
a one-to-one interconnection with another
Model 373A (or any other Ultimo-based
product). An Ethernet switch linking the two
Ultimo-based units is required to success-
fully interconnect them. The technical rea-
son that a switch is required relates to the
need for a slight latency (delay) in the data
flow; an Ethernet switch will provide this.
While this is certainly an anomaly, since PoE
power is required for Model 373A operation
it’s highly unlikely that an application would
use two Model 373A units without a PoE-
enabled Ethernet switch being present.