Studio Technologies 342 User manual

50295-0422, Issue Preliminary 1
Copyright © 2022 by Studio Technologies, Inc., all rights reserved
studio-tech.com
User Guide
Issue Preliminary 1, April 2022
This User Guide is applicable for serial numbers
M342-00151 and later with main rmware version 1.00 and later
and STcontroller application version 3.08.00 and later.
Model 342
Intercom Station

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Model 342 User Guide Issue Preliminary 1, April 2022
Studio Technologies, Inc. Page 3
Model 342
INTERCOM STATION
Table of Contents
Revision History ......................................................................................................... 4
Introduction ................................................................................................................ 5
Getting Started ........................................................................................................... 7
Dante Conguration ................................................................................................... 8
Model 342 Conguration ........................................................................................... 10
Operation .................................................................................................................. 13
Technical Notes......................................................................................................... 15
Specications ............................................................................................................ 18
Appendix A: STcontroller Default Conguration Values ............................................ 19

Issue Preliminary 1, April 2022 Model 342 User Guide
Page 4 Studio Technologies, Inc.
Model 342
INTERCOM STATION
Revision History
Issue Preliminary 1, April 2022:
•Initial preliminary release.

Model 342 User Guide Issue Preliminary 1, April 2022
Studio Technologies, Inc. Page 5
Model 342
INTERCOM STATION
Introduction
The Model 342 Intercom Station is a compact, desktop
device that supports two channels of talk and listen. The
unit begins with the features o󰀨ered by traditional analog
party-line (PL) intercom user devices and adds a range of
new capabilities, along with the advanced performance and
exibility that Dante® audio-over-Ethernet provides. Over a
standard IP network, multiple Model 342 Intercom Station
units and other compatible Studio Technologies’ products
can be used to create party-line intercom applications with
help from an external Dante-enabled audio matrix such as
the Studio Technologies’ Model 5421 or Model 5422A Dante
Intercom Audio Engines. Alternately, Model 342 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
congured using the STcontroller software application. Con-
gurable parameters include electret microphone power,
microphone preamplier gain, talk button operation, status
LED action and intensity, sidetone operation, and head-
phone channel assignment. Hardware features include
dual-channel (stereo) headphone output, dual headset con-
nectors, integrated sidetone, call signal receive display, and
remote mic kill (“talk o󰀨”). The range of capabilities, along
with the excellent audio quality supported by the digital
audio path, o󰀨ers a unique and powerful user experience.
Setting up and conguring a Model 342 is simple. An ether-
CON®RJ45 receptacle is used to interconnect with a stan-
dard twisted-pair Ethernet port associated with a local-area
network (LAN). This connection provides both power and
bidirectional digital audio. The unit is compatible with both
broadcast and “gaming” headsets. A “professional” broad-
cast or intercom-style headset with a dynamic or electret
(DC-powered) microphone can be interfaced with a Model
342 using a 5-pin XLR connector. The Model 342 also
directly supports connection of earbuds or gaming headsets
that utilize a 3.5 mm 4-conductor (TRRS) CTIA-compliant
plug. These moderately priced devices, commonly associ-
ated with mobile phones or personal computers, are often
of high quality and may be the preferred headset for some
applications. With the Model 342’s moderate price and
ability to support a broad range of headsets, the overall
cost of deploying a high-performance intercom system can
often meet budget goals.
The STcontroller software application is used to select the
Model 342’s operating parameters. Versions are available,
free of charge, that support the Windows®and macOS®
operating systems. The two LED-illuminated talk push-
button switches can be independently configured for
optimal operation. Two “push-in/push-out” (“pop-out”) rotary
controls make it easy to set and maintain the desired head-
phone output level. The Model 342’s compact enclosure is
made from steel which o󰀨ers both stability and ruggedness.
The audio quality of the Model 342 is excellent, 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 supported,
including education and commercial theater, sports and
entertainment TV and radio events, streaming broadcasts,
house-of-worship, corporate and government AV, post
production, and aerospace.
Dante Audio-over-Ethernet
Audio data is sent to and received from the Model 342
using the Dante audio-over-Ethernet media networking
technology. As a Dante-compliant device, the Model 342’s
two Dante transmitter (output) and two Dante receiver
(input) channels will be routed (subscribed) with other
devices using the Dante Controller software application.
The digital audio’s bit depth is up to 24 with a sampling
rate of 48 kHz. The Model 342 is AES67-compliant and
is compatible with the Dante Domain Manager™ (DDM)
software application.
Figure 1. Model 342 Intercom Station front and
back views

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Page 6 Studio Technologies, Inc.
Model 342
INTERCOM STATION
Dual-color LEDs provide status indications of the Dante
interface. The Dante Identify command can take on a
unique role with the Model 342. Not only can it cause the
two talk pushbutton switches to light orange in a highly
visible sequence, it can be congured to turn o󰀨 (“kill”) the
talk functions if either or both are active.
Audio Quality
The Model 342 o󰀨ers “pro” audio performance that is not
found in typical party-line (PL) intercom devices. A low-
noise, wide dynamic-range microphone preamplier and
associated voltage-controlled-amplier (VCA) dynamics
controller (compressor) ensures that microphone audio
quality is preserved while minimizing the chance of signal
overload. DC power to support electret microphones can be
enabled as required. 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 (input)
channels. The supported sampling rate is 48 kHz with a bit
depth of up to 24. The audio signals pass into the Model
342’s processor where channel routing, headphone level
control, and sidetone creation are performed within the
digital domain. This provides exibility, allowing precise
control of the audio signals and eliminating the need for
the two rotary level controls from having to directly han-
dle 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.
Call Receive Function
A call receive function allows Model 342 users to be pro-
vided with a visual indication that a call signal is active on a
Dante receiver (input) channels. The cadence of the visual
indication can be congured to meet an application’s needs.
Using 20 kHz tones, the call signals are sent within the
Dante audio channels (“in band”) allowing interoperability
between multiple Studio Technologies’ beltpack 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.
Conguration Flexibility
A highlight of the Model 342 is its ability to be easily cong-
ured to meet the needs of specic users and applications.
All conguration choices are made using the STcontroller
software application that communicates with the Model 342
by way of an Ethernet network connection. Congurable
parameters include microphone power and preamplier
gain, headphone monitoring, sidetone operation, call
receive cadence, and talk button operation.
The microphone input can be selected for compatibility
with dynamic or electret (DC-powered) microphones. The
gain of the microphone preamplier can be selected from
among five choices. These choices allow compatibility
with the variety of microphones that are part of broadcast,
intercom, and computer gaming headsets.
To support optimum user performance, the Model 342’s two
talk pushbutton switches can be independently congured
from among four choices: Push to Talk, Latching, Push to
Talk/Tap to Latch, or Disabled. Two audio channels arrive
via Dante receiver (input) channels 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 head-
phone channels. This exibility allows a variety of listening
environments to be created, including stereo, dual-channel
monaural, and single-channel monaural.
Ethernet Data and PoE
The Model 342 connects to an Ethernet data network
using a standard 100 Mb/s twisted-pair Ethernet interface.
The physical interconnection is made by way of a Neutrik®
etherCON RJ45 receptacle. While compatible with standard
RJ45 plugs, etherCON allows a ruggedized and locking
interconnection for harsh or high-reliability environments.
An LED, located on the unit’s back panel, displays the
status of the network connection.
The Model 342’s operating power is provided by way of the
Ethernet interface using the 802.3af Power-over-Ethernet
(PoE) standard. This allows fast and e󰀩cient interconnec-
tion with an associated data network. To support PoE power
management, the Model 342’s PoE interface reports to the
power sourcing equipment (PSE) that it’s a class 1 (very
low power) device.
Future Capabilities and Firmware
Updating
The Model 342 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 (un-
derneath the unit’s cover), allows the application rmware
(embedded software) to be updated using a standard USB
ash drive. The Model 342 uses the UltimoX2™ integrated
circuit from Audinate to implement its Dante interface. The
rmware in this integrated circuit can be updated via the
Ethernet connection, helping to ensure that its capabilities
remain up to date.

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Model 342
INTERCOM STATION
Getting Started
What’s Included
Included in the shipping carton are a Model 342 Intercom
Station and information 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 may be made
using the three connectors located on the back of the
Model 342’s enclosure. 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. Alternately, a
headset with a 3.5 mm 4-conductor TRRS plug can be
used. (The headset’s plug needs to follow the CTIA™/AHJ
conguration standard.)
Ethernet Connection with PoE
A 100BASE-TX Ethernet connection that supports
Power-over-Ethernet (PoE) is required for Model 342
operation. This one connection will provide both the Ether-
net data interface and power for the Model 342’s circuitry.
A 10BASE-T connection is not su󰀩cient. A 1000BASE-T
(GigE) connection is not supported unless it can automat-
ically “fall back” to 100BASE-TX operation. The Model 342
supports Ethernet switch power management, enumerat-
ing itself as a PoE class 1 device. Any PoE source that is
compliant with the IEEE® 802.3af standard will function
correctly. Should the selected Ethernet switch port support
Energy-E󰀩cient Ethernet (EEE) it must be disabled to help
ensure reliable Dante operation. (This is applicable for all
Dante-compatible products.)
The Ethernet connection is made by way of an etherCON
RJ45 jack that is located on the Model 342’s back panel.
This allows connection by way of a RJ45 plug that’s part of
a typical Ethernet “patch cable.” Alternately, a twisted-pair
data cable terminated with an etherCON plug can be
utilized. A crossover cable will never be required as the
Model 342’s Ethernet interface supports auto MDI/MDI-X.
The maximum cable distance is 100-meters (325-feet) for
twisted-pair Ethernet cabling.
Headset Connections
The Model 342 allows two di󰀨erent types of headsets to be
connected. A 5-pin female XLR connector is provided on the
unit’s back panel to support connection of a “professional”
broadcast- or intercom-style communications headset.
A 3.5 mm 4-conductor TRRS jack allows a computer
gaming headset to be directly connected. The Model 342’s
two headset connectors are electrically wired in parallel.
As such, only one type of headset should be connected
at one time.
Headset A
The Model 342 provides a 5-pin female XLR connector that
interfaces with the microphone and headphone connections
of a single- or dual-ear intercom- or broadcast-style head-
set. The connector is labeled Headset A. Refer to Figure 2
for connection details. The microphone input connections
are compatible with most unbalanced dynamic or elec-
tret (low-voltage DC-powered) microphones. A balanced
dynamic microphone should, in most cases, also function
correctly if its signal – (low) is connected to Model 342’s
mic in –/shield connection. No support is provided for
microphones that require P12 or P48 phantom power.
To allow users of stereo (dual-earpiece or “double mu󰀨”)
headsets to hear a monaural version of the two headphone
output channels does not require special wiring of the 5-pin
male XLR mating connector. The headset’s left headphone
channel should always be wired to pin 4 and the right head-
phone channel to pin 5. Conguration choices, discussed
in a later section, can then be used to create the desired
monaural output. It’s important not to connect together
(short) pins 4 and 5 of the headset’s connector as damage
to the Model 342’s output circuitry could result.
A monaural (single-earpiece or “single muff”) headset
should be wired such that its headphone is wired only to
pin 4; pin 5 should be remain unused. Conguration choic-
es, discussed in a later section, can be used to create a
single-channel monaural output.
Figure 2. Headset A connection pinout chart

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Page 8 Studio Technologies, Inc.
Model 342
INTERCOM STATION
It’s possible that some beyerdynamic headset interconnect-
ing cable assemblies terminate the earpiece’s left and right
connections opposite from what the Model 342 and other
broadcast equipment require. These cables may terminate
the left earpiece to pin 5 of a 5-pin male XLR connector and
the right earpiece to pin 4. If this condition is present, it will
require reversing or “ipping” the two wires in the headset’s
connector such that the left earpiece connects to pin 4 and
the right earpiece to pin 5.
If a separate microphone and pair of headphones need
to be connected then an adapter cable assembly should
be fabricated. It would consist of a 5-pin male XLR con-
nector wired to both a 3-pin female XLR connector for the
microphone and a ¼-inch or 3.5 mm TRS jack for the head-
phones. In this scenario, the microphone would, in most
cases, be a dynamic type as the Model 342 provides only
low-voltage DC “electret” power. Most hand-held or “stick”
microphones are dynamic and should function correctly.
But phantom-powered (P12 or P48) microphones would
not be compatible.
Headset B
The Model 342 also allows direct connection of gaming
headsets that are ubiquitous in the personal computer
world. The 3.5 mm 4-conductor (TRRS) jack, labeled
Headset B, is compatible with the CTIA/AHJ congura-
tion standard which has the headphone left channel on
the tip connection, the headphone right channel on the
ring 1 connection, common on the ring 2 connection, and
the microphone on the sleeve connection. Compatible
headsets are readily available, typically described as “per-
sonal computer” or “gaming” headsets. The microphones
used in these headsets are electret type which require a
low-voltage DC source for operation. The Model 342 is able
to provide this power and requires only that the appropriate
setting in STcontroller be selected. Refer to Figure 3 for a
detailed description of the compatible 3.5 mm plug.
Dante Conguration
For audio to pass to and from the Model 342 requires that
several Dante-related parameters be congured. These
conguration settings will be stored in non-volatile memory
within the Model 342’s circuitry. Conguration will typically
be done with the Dante Controller software application,
available for download free of charge at audinate.com.
Versions of Dante Controller are available to support
various personal computer operating systems. The Model
342 uses the UltimoX2 2-input/2-output integrated circuit to
implement its Dante interface. The unit is compatible with
the Dante Domain Manager (DDM) software application.
Audio Routing
The two Dante receiver (input) channels associated with
the Model 342 need to be routed (subscribed) to Dante
transmitter (output) channels on associated equipment.
Conguration settings in the STcontroller software applica-
tion allow these two audio sources to be sent to the Model
342’s 2-channel headphone output. The Model 342’s two
Dante transmitter (output) channels must be routed (sub-
scribed) to Dante receiver (input) channels on associated
equipment. This achieves routing the Model 342’s two talk
output audio channels to the device (or devices) that will
be “listening” to them.
Within Dante Controller, a “subscription” is the term used
for routing a transmitter channel or ow (a group of up to
four output channels) to a receiver channel or ow (a group
of up to four input channels). The number of transmitter
flows associated with an UltimoX2 integrated circuit is
limited to two. These can either be unicast, multicast, or
a combination of the two. If the Model 342’s transmitter
(output) channels need to be routed using more than two
ows it’s possible that an intermediary device, such as the
Studio Technologies’ Model 5422A Dante Intercom Audio
Engine, can be used to “repeat” the signals.
Unit and Channel Names
The Model 342 has a default Dante device name of
ST-M342- followed by a unique su󰀩x. The su󰀩x identi-
es the specic Model 342 that is being congured. The
su󰀩x’s actual alpha and/or numeric characters relate to
the MAC address of the unit’s UltimoX2 integrated circuit.
The Dante transmitter (output) channels have the default
names of Ch1 and Ch2. The two Dante receiver (input)
channels have default names of Ch1 and Ch2. Using
the Dante Controller application, the default device name
and channel names can be revised as appropriate for the
specic application.
Figure 3. Headset B (TRRS) connection pinout chart

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Studio Technologies, Inc. Page 9
Model 342
INTERCOM STATION
Device Conguration
The Model 342 only supports an audio sample rate of
48 kHz with no pull-up/pull-down values available. The
audio encoding is xed for PCM 24. Device Latency and
Clocking can be adjusted if required but the default value
is typically correct.
Network Conguration – IP Address
By default, the Model 342’s Dante IP address and related
network parameters will be determined automatically using
DHCP or, if not available, the link-local network protocol. If
desired, Dante Controller allows the IP address and related
network parameters to be manually set to a xed (static)
conguration. While this is a more-involved process than
simply letting DHCP or link-local “do their thing,” if xed
addressing is necessary then this capability is available. In
this case, it’s highly recommended that a unit be physically
marked, e.g., directly using a permanent marker or “console
tape,” with its specic static IP address. If knowledge of a
Model 342’s IP address has been misplaced there is no
reset button or other method to easily restore the unit to a
default IP setting.
AES67 Conguration – AES67 Mode
The Model 342 can be congured for AES67 operation.
This requires the AES67 Mode to be set for Enabled. By
default, AES67 mode is set for Disabled. Note that in the
AES67 mode the Dante transmitter (output) channels will
function in multicast; unicast is not supported.
Model 342 Clocking Source
While technically the Model 342 can serve as a Leader
clock for a Dante network (as can all Dante-enabled
devices) in virtually all cases the unit will be congured to
receive “sync” from another device. As such, the check box
for Preferred Leader associated with the Model 342 would
not be enabled.

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Page 10 Studio Technologies, Inc.
Model 342
INTERCOM STATION
Model 342 Conguration
The STcontroller software application is used to congure the way in which the Model 342 functions. No DIP switch settings
or other local actions are used to congure the unit. This makes it imperative that STcontroller be available for convenient
use on a personal computer that’s connected to the related LAN.
Installing STcontroller
STcontroller is available, free of charge, on the Studio Technologies’ website (studio-tech.com). Versions are available
that are compatible with personal computers running selected versions of the Windows and macOS operating systems.
If required, download and install STcontroller onto a designated personal computer. This personal computer must be on
the same local area network (LAN) and subnet as the Model 342 units that are to be congured. Immediately after starting
STcontroller the application will locate all the Studio Technologies’ devices that it can control. The one or more Model
342 units to be congured will appear in the device list. Use the Identify command to allow easy recognition of a specic
Model 342 unit. Double-clicking on a device name will cause the associated conguration menu to appear. Review the
current conguration and make any changes that are desired.
Changes made using STcontroller will be immediately reected in the unit’s operation; no Model 342 reboot is required.
Each time a change is made the two talk pushbutton switches, located on the Model 342’s front panel, will ash orange
to indicate that a command from STcontroller has been received.
Parameters
Microphone Input – Electret Power
Choices are Enabled or Not Enabled (box checked or not).
Enable the Electret Power check box if the connected
headset has an electret microphone that requires a source
of low-voltage DC power for operation. The electret power
on/o󰀨 status is displayed by way of a red LED, labeled
MIC PWR, that is located on the back of the Model 342’s
enclosure adjacent to the headset connector. Whenever
the PWR LED is lit, 3.3 volts DC is being provided to the
headset connectors.
In virtually all cases, gaming or computer headsets that
use a 3.5 mm TRRS plug will require microphone power.
If the associated headset has a dynamic (non-powered)
microphone do not enable the Electret Power check box.
Most broadcast headsets that terminate on 5-pin male XLR
connectors will not require microphone power.
Note that the Model 342 cannot supply P12 or P48 phan-
tom power that may be required for balanced condenser
(capacitor) microphones. This should not pose an issue as
this type of microphone is essentially never associated with
a headset that would be used for intercom applications.