Studio Technologies 370A Data Sheet

Model 370A Intercom Beltpack

Two Channels, Dante® Technology

Key Features

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Dante audio-over-Ethernet technology

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Two independent talk and listen channels

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Integrated call function

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Supports dynamic and electret microphones

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5-pin female XLR headset connector

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Excellent audio quality

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Uses STcontroller for configuration

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AES67 and Dante Domain Manager™ support

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Power-over-Ethernet (PoE) powered

Introduction

The Model 370A Intercom Beltpack begins with the fea-

tures offered by traditional 2-channel party-line intercom

user devices and adds a range of new capabilities, along

with the advanced performance and flexibility that Dante®

audio-over-Ethernet provides. Over a standard IP network,

multiple Model 370A units can be used in party-line (PL)

intercom applications with help from an external Dante-

enabled audio matrix such as the Studio Technologies

Model 5422 Dante Intercom Audio Engine. Alternately,

units can be used “point-to-point” or interfaced with Dante-

compatible matrix intercom systems.

Only a single Power-over-Ethernet (PoE) connection is

required for operation. Key user features can be easily

configured using the STcontroller software application.

Configurable parameters include electret microphone pow

ering, microphone preamplifier gain, talk button operation,

and headphone channel assignment. User features include

integrated sidetone, call function, and remote mic kill (“talk

off”). The wide range of capabilities, along with the excel

lent audio quality provided by the digital audio signal path,

offers a unique and powerful user experience.

Set up and configuration of the Model 370A is simple. An

etherCON® RJ45 receptacle is used to interconnect with

a standard twisted-pair Ethernet port associated with a

local-area network (LAN). This connection provides both

power and bidirectional digital audio. A broadcast or in

tercom-style stereo or monaural headset with a dynamic

or electret (DC-powered) microphone interfaces with the

unit using a 5-pin XLR connector.

The STcontroller software application is used to select the

unit’s operating parameters. Two talk pushbutton switches

can be configured for optimal operation. Two push-in/push-

out (“pop out”) rotary controls make it easy to set and

maintain the desired headphone output level. The Model

370A’s enclosure is made from an aluminum alloy which

offers both light weight and ruggedness. A stainless steel

“belt clip,” located on the back of the unit, allows direct

attachment to a user’s clothing.

The audio quality of the Model 370A’s audio channels is ex

cellent, with low distortion, low noise, and high headroom.

Careful circuit design and rugged components ensure long,

reliable operation. A wide range of applications can be sup

ported, including sports and entertainment TV and radio

events, streaming broadcasts, corporate and government

AV installations, and post-production facilities.

Dante Audio-over-Ethernet

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Audio data is sent to and received from the Model 370A

using the Dante audio-over-Ethernet media networking

technology. As a Dante-compliant device, the Model 370A’s

two audio output (Dante transmitter) and two audio input

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(Dante receiver) channels can be interconnected (routed)

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50635-0618, Issue 1

with other devices using the Dante Controller software

application. The Dante transmitter and receiver channels

are limited to supporting four Dante flows, two in each

direction. The digital audio’s bit depth is up to 24 with a

sampling rate of 48 kHz. The Model 370A is AES67 com

patible and compliant with the Dante Domain Manager™

software application.

Two bi-color LEDs provide an indication of the Dante con

nection status. The Dante Controller’s

Identify

command

takes on a unique role with the Model 370A. Not only will

it cause the talk and call button LEDs to light in a unique

highly visible sequence, it can also be configured to turn

off any active talk channels.

Call Function

A call function allows Model 370A users to send and

receive channel-specific visual alert signals. Pressing the

call pushbutton on the top of the unit is all that’s required

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to signal other users that attention is requested. Using 20

kHz tones, the call signals are sent within the audio chan

nels (“in band”) allowing interoperability between multiple

Model 370A units as well as being compatible with legacy

­party-line intercom systems. Call signals can be useful to

indicate to users that they are needed “on headset” or

should be actively listening to an intercom channel. The

call function can also be used to provide real-time cues to

production personnel during the running of live events.

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Audio Quality

The Model 370A’s completely “pro” performance is

counter to the less-than-stellar reputation of typical

party-line (PL) intercom audio. A low-noise, wide dynamic-

range microphone preamplifier and associated voltage-

controlled-amplifier (VCA) dynamics controller (compres

sor) ensures that microphone audio quality is preserved

while minimizing the chance of signal overload. DC power

to support electret microphones can be enabled if neces

sary. The output of the microphone preamp and compressor

is routed to an analog-to-digital converter (ADC) section

that supports a sampling rate of 48 kHz with a bit depth

of up to 24. The audio signal, now in the digital domain,

travels through the processor and on to the Dante interface

section where it is packetized and prepared for transport

over Ethernet.

Audio input signals arrive via two Dante receiver channels.

The supported sampling rate is 48 kHz with a bit depth

of up to 24. The audio signals pass into the Model 370A’s

processor where channel routing, headphone level control,

and sidetone creation are performed within the digital

domain. This provides flexibility, allowing precise control

of the audio signals and eliminating the need for the two

rotary level controls from having to directly handle analog

audio signals. The audio signals destined for the 2-channel

headphone output are sent to a high-performance digital-

to-analog converter and then on to robust driver circuitry.

High signal levels can be provided to a variety of headsets,

headphones, and earpieces.

Configuration Flexibility

A highlight of the Model 370A is its ability to be easily

configured to meet the needs of specific users and ap

plications. All configuration choices are made using the

STcontroller software application that communicates with

the Model 370A by way of an Ethernet network connection.

­Configurable parameters include microphone power and

preamplifier gain, sidetone audio operation, talk button

operation, and headphone monitoring.

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The microphone input can be selected for compatibility with

dynamic or elected (DC-powered) microphones. The gain

of the microphone preamplifier can be selected from among

four choices, two for supporting dynamic microphones and

two for supporting electret microphones. These choices

allow compatibility with the variety of microphones that

are part of broadcast and intercom headsets.

A unique Model 370A feature is the ability to individu

ally configure the way in which the two talk pushbutton

switches function; four choices are available. For standard

intercom beltpack operation it’s typical to select

Talk

,

Latching

, or

Push to Talk/Tap to Latch

. For situations

where only monitoring of an intercom channel is desired a

Disabled

mode is available.

Two audio channels arrive via Dante and are destined for

the 2-channel headphone output. Each input source can be

independently routed to the left headphone channel, right

headphone channel, or both the left and right headphone

channels. This flexibility allows a variety of listening envi

ronments to be created, including stereo, single-channel

monaural, and dual-channel monaural.

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Push to

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Studio Technologies, Inc. Model 370A Intercom Beltpack, Issue 1, Page 2