User Guide

Issue 4, February 2021 Model 374A User Guide
Page 8 Studio Technologies, Inc.
MODEL 374A
INTERCOM BELTPACK
Future Capabilities and
Firmware Updating
The Model 374A was designed such that
its capabilities and performance can be
enhanced in the future. A USB connector,
located on the unit’s main circuit board
(underneath the unit’s cover), allows the
application firmware (embedded software)
to be updated using a USB flash drive.
The Model 374A uses Audinate’s Ultimo™
integrated circuit to implement the Dante
interface. The firmware in this integrated
circuit can be updated via the Ethernet
connection, helping to ensure that its ca-
pabilities remain up to date.
Getting Started
What’s Included
Included in the shipping carton are a
Model 374A Intercom Beltpack and in-
structions on how to obtain an electronic
copy of this guide. As a device that is
Power-over-Ethernet (PoE) powered, no
external power source is provided. In most
applications an Ethernet switch with the
required PoE capability will be utilized.
Connections
In this section signal interconnections will
be made using the two connectors located
on the bottom of the Model 374A’s enclo-
sure. An Ethernet data connection with
Power-over-Ethernet (PoE) capability will
be made using either a standard RJ45
patch cable or an etherCON protected
RJ45 plug. A dual-channel or single-
channel (dual- or single-ear) headset
will be connected using a cable-mounted
5-pin male XLR connector.
Ethernet Connection with PoE
A 100BASE-TX Ethernet connection that
supports Power-over-Ethernet (PoE) is re-
quired for Model 374A operation. This one
connection will provide both the Ethernet
data interface and power for the Model
374A’s circuitry. A 10BASE-T connection
is not sufficient and a 1000BASE-T (GigE)
connection is not supported unless it can
automatically “fall back” to 100BASE-TX
operation. The Model 374A supports Eth-
ernet switch power management, enumer-
ating itself as a PoE class 1 device. Any
source that is compliant with the IEEE®
802.3af standard will function correctly.
Should the selected Ethernet switch port
support Energy-Efficient Ethernet (EEE) it
must be disabled to help ensure reliable
Dante operation.
The Ethernet connection is made by way
of a Neutrik etherCON protected RJ45
receptacle that is located on the bottom
of the Model 374A’s enclosure. This allows
connection by way of a cable-mounted
etherCON connector or a standard RJ45
plug. The Model 374A’s Ethernet interface
supports auto MDI/MDI-X so that a cross-
over cable will never be required.
Headset Connection
The Model 374A provides a 5-pin female
XLR connector that interfaces with the
microphone and headphone connec-
tions of an intercom or broadcast-style
headset. Refer to Figure 2 for connection
details. The microphone input connections
are compatible with most unbalanced
dynamic or electret (low-voltage DC-pow-
ered) microphones. A balanced dynamic
microphone should, in most cases, also
function correctly if the signal – (low) is
connected to Model 374A’s mic in –/shield