Studio Technologies 348 User manual

Copyright © 2019 by Studio Technologies, Inc., all rights reserved
www.studio-tech.com
User Guide
Issue Preliminary 2, November 2019
This User Guide is applicable for serial numbers
M348-00151 and later with main firmware version 1.05 and later
and STcontroller application version 2.05.00 and later.
50291-1119, Issue Preliminary 2
Model 348 Intercom Station

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Model 348 User Guide Issue Preliminary 2, November 2019
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MODEL 348
INTERCOM STATION
Table of Contents
Revision History ........................................................... 4
Introduction ......................................................... Pending
Getting Started .............................................................. 5
Configuration ................................................................ 8
Operation ..................................................................... 15
Technical Notes ............................................................ 25
Specifications ............................................................... 28
Appendix A ................................................................... 30

Issue Preliminary 2, November 2019 Model 348 User Guide
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MODEL 348
INTERCOM STATION
Revision History
Issue Preliminary 2, November 2019:
• Added the Getting Started and Operation sections.
Issue Preliminary 1, September 2019:
• Initial preliminary release.

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MODEL 348
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Introduction
Pending
Getting Started
What’s Included
Included in the shipping carton are a Model
348 Announcer’s Console and a printed
copy of this guide. As a device that can be
Power-over-Ethernet (PoE) powered, no
external power source is provided. This is
because in most applications an Ethernet
switch with PoE capability will be utilized. It’s
also possible to connect an external source
of 12 volts DC to power the Model 348. If
this is the case then a power supply would
need to be provided separately.
Connections
In this section signal interconnections will
be made using the connectors located on
the back of the Model 348’s enclosure. In
addition, it’s possible that a gooseneck
microphone will be attached via the ¼-inch
jack located on the top surface of the unit.
One or two Ethernet connections will be
made using either standard RJ45 patch
cables or etherCON protected RJ45 plugs.
The Ethernet data connection associated
with the primary RJ45 connector is com-
patible with Power-over-Ethernet (PoE). If
desired, an Ethernet connection made to the
secondary Ethernet connector can provide
access to a redundant Dante network. Or it
can be utilized as an active “loop through”
connection associated with the primary
Ethernet connection. If PoE is not going to
be utilized, or a redundant source of power
is desired, a source of 12 volts DC can be
connected by way of a 4-conductor XLR
connector.
A dual-channel or single-channel (dual- or
single-ear) headset can be connected using
a cable-mounted 5-pin male XLR connector.
Alternately, a “computer” headset with a 3.5
mm 4-conductor TRRS plug can be used. An
electret gooseneck microphone that has an
integrated ¼-inch plug can be connected.
One or Two Ethernet Connections
One 1000BASE-T (“GigE”) Ethernet connec-
tion is required for Model 348 operation. If
available and connected to the primary RJ45
connector, this connection can provide both
the Ethernet data interface and power for the
Model 348’s circuitry. A 10BASE-T connec-
tion is not sufficient. A 100BASE-TX connec-
tion may be adequate but not optimal.
Figure 1. Model 348 Intercom Station front and back views

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MODEL 348
INTERCOM STATION
A second 1000BASE-T (“GigE”) connection
can be made if redundant Dante is desired.
The Model 348’s network configuration must
be set for redundant for this functionality to
be active. PoE is not supported on the sec-
ondary Ethernet connection. The secondary
Ethernet port can also be used as a “loop
through” port such as would be provided by
an Ethernet switch. This requires that the
Model 348’s network configuration is set
for switched. Switched mode is the default
setting but using the secondary port in this
mode for applications other than trouble-
shooting is not recommended. It will function
reliably but “daisy chaining” Ethernet signals
can limit flexibility and present a failure point.
The Ethernet connections are made by way
of two Neutrik etherCON protected RJ45
connectors that are located on the back of
the Model 348’s enclosure. These allow con-
nection by way of cable-mounted etherCON
connectors or standard RJ45 plugs. The
Model 348’s Ethernet interface supports auto
MDI/MDI-X so that a crossover cable is not
required. The Model 348’s primary Ethernet
connection does not enumerate itself as a
specific PoE class. As such, a PoE power-
sourcing-equipment (PSE) port will consider
the device as a class 0 device which could
use up to 12.94 watts of power.
External 12 Volts DC Input
An external source of 12 volts DC can be
connected to the Model 348 by way of the 4-
pin male XLR connector which is located on
the back panel. While the requirement for the
external source is nominally 12 volts, correct
operation will take place over a 10 to 18 volt
range. The Model 348 requires a maximum
of 600 milliamperes (0.6 amperes) at 12 volts
DC for correct operation. The DC source
should be terminated to a 4-pin female XLR
connector with pin 1 negative (–) and pin 4
positive (+).
If an external power source is required, the
PS-DC-02 power supply, available as an
option from Studio Technologies, is directly
compatible with the Model 348. Its AC mains
input allows connection to 100-240 volts,
50/60 Hz with an output of 12 volts DC, 1.5
amperes maximum. Its DC output is termi-
nated on a 4-pin female XLR connector.
As previously discussed in this guide, an
Ethernet connection that provides power-
over-Ethernet (PoE) can serve as the Model
348’s power source. Alternately, an exter-
nal 12 volts DC source can be connected.
For redundancy, both PoE and the external
source can be connected at the same time.
If both PoE and an external 12 volts DC
source are connected, power will be drawn
only from the PoE supply. If the PoE source
becomes inoperative the 12 volts DC source
will provide the Model 348’s power. No inter-
ruption in operation will occur during a power
source transition.
Headset Connections
The Model 348 allows two different types of
headsets to be connected. A 5-pin female
XLR connector, located on the Model 348’s
back panel, allows connection of a standard
broadcast- or intercom-style communica-
tions headset. A 3.5 mm 4-conductor TRRS
jack, also located on the back panel, allows
a computer gaming headset to be directly
connected. The Model 348’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 348 provides a 5-pin female XLR
connector that interfaces with the micro-
phone and headphone connections of a sin-
gle- or dual-ear intercom or broadcast-style
headset. The connector is labeled Headset
A. Refer to Figure 2 for connection details.

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MODEL 348
INTERCOM STATION
The microphone input connections are
compatible with most unbalanced dynamic
or electret (low-voltage DC-powered) micro-
phones. A balanced dynamic microphone
should, in most cases, also function correctly
if its signal – (low) is connected to Model
348’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-muff”) headsets to hear a monaural
version of the two headphone output chan-
nels does not require special wiring of the
5-pin male XLR mating connector. The head-
set’s left headphone channel should always
be wired to pin 4 and the right headphone
channel to pin 5. Software-based configura-
tion choices, discussed later in this guide,
can be used to create the desired monaural
output. It’s important not to connect together
(short) pins 4 and 5 of the headset’s con-
nector as damage to the Model 348’s output
circuitry could result.
A monaural (single-earpiece or “single-muff”)
headset should be wired such that its head-
phone is wired only to pin 4; pin 5 should
be remain unused. Configuration choices,
discussed later in this guide, can be used to
create a monaural output.
It’s possible that some Beyerdynamic head-
set interconnecting cable assemblies termi-
nate the earpiece’s left and right connections
opposite from what the Model 348 and other
broadcast equipment require. These cables
may terminate the left earpiece to pin 5 of
the 5-pin male XLR connector and the right
earpiece to pin 4. If this condition is present
it will require reversing or “flipping” the two
wires in a 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 stereo
or monaural headphones need to be con-
nected an adapter cable assembly must be
fabricated. It would consist of a 5-pin male
XLR connector 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 348 provides only low-voltage DC
electret power. Phantom-powered (P12 or
P48) microphones would not be compatible.
Most hand-held or “stick” microphones are
dynamic and should function correctly.
Headset B
The Model 348 also allows direct connec-
tion 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 configu-
ration standard which has the headphone
left channel on the tip connection, the head-
phone right channel on the ring 1 connec-
tion, common on the ring 2 connection, and
the microphone on the sleeve connection.
Compatible headsets are readily available,
typically described as personal computer or
gaming headsets. The microphones used in
these headsets are electret type which re-
quire a low-voltage DC source for operation.
Figure 2. Headset A connection pinout chart

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MODEL 348
INTERCOM STATION
The Model 348 is able to provide this power
and requires only that the appropriate setting
in the STcontroller personal computer soft-
ware application be selected. Refer to Figure
3 for a detailed description of the compatible
TRRS plug.
The Model 348’s gooseneck bushing includes
a hex head socket set screw with a thread
pitch of 4-40. This allows the gooseneck
microphone to be secured into the bushing
by simply tightening the set screw against
the microphone using a 5/64 hex driver. In
many cases, especially in applications where
the Model 348 will be moved from venue-to-
venue, it will not be optimal for the hex screw
to be utilized. This is because the gooseneck
microphone may need to be removed and
stored for transit. In this case the set screw
should be removed and stored.
Configuration
The STcontroller software application is used
to configure the way in which the Model 348
functions. No DIP switch settings or other
local actions are used to configure 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 (www.studio-
tech.com/stcontroller-application/) and is
compatible with personal computers running
Windows operating systems that are version
7 and later. STcontroller versions 2.05.00 and
later are required to fully support the Model
348. If required, download and install STcon-
troller onto a designated personal computer.
This personal computer must be on the same
local area network (LAN) and subnet as the
Model 348 units that are to be configured. Im-
mediately after starting STcontroller the appli-
cation will locate all the Studio Technologies’
devices that it can control. The one or more
Model 348 units to be configured will appear
in the device list. Use the Identify command
to allow easy recognition of a specific Model
348 unit. Double-clicking on a device name
Figure 3. Headset B (TRRS) connection pinout
chart
Gooseneck Microphone
The Model 348 allows the connection of a
broadcast-standard gooseneck microphone.
A threaded combination bushing/3-conduc-
tor 1/4-inch jack is incorporated into the top
panel of the unit. It’s expected that Studio
Technologies will offer a compatible goose-
neck microphone (a release date has not
been established as of the writing of this
guide). The RTS/Telex/Bosch MCP-90-se-
ries is also directly compatible and performs
very well. The two main requirements for the
gooseneck microphone are that it contain an
electret microphone and the interconnection
be in the form of a ¼-inch 3-conductor plug
with integrated threads that have a pitch
7/16-20 UNF.
The 3-conductor ¼-inch jack associated with
the Model 348’s bushing has a tip connec-
tion that is used for both microphone audio
as well as for supplying the low-voltage DC
needed for powering the electret micro-
phone. The ring connection is used for the
microphone low signal and the sleeve con-
nection is chassis ground. Within the Model
348’s circuitry the ring and sleeve connec-
tions are connected together as well as be-
ing “tied” (connected) to the chassis.

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will cause the associated configuration menu
to appear. Review the current configuration
and make any changes that are desired.
Parameters
The configurable functions include:
General menu page:
• Microphone Input – Headset Mic Power
• Microphone Input – Headset Mic Gain
• Microphone Input – Gooseneck Mic Gain
• Headset – Sidetone Level
• Headset – Dim
• Speaker – Source
• Speaker – Dim
• Dante Monitor Outputs – Mode
• Dante Monitor Outputs – Dim
• System – Level Control Position Display
• System – Signal Present Display
• System – LED Intensity
• System – Headset and Monitor Outputs
Follow Mic Source
• System – Hot Mic
• System – Monitor A Call Tone Level
• System – Monitor B Call Tone Level
Channel Specific menu page (independent
configuration settings for channels 1-8):
• Button Mode
• Button Function
• IFB Program Dim
• Headset Routing
• Monitor Routing
• Call Indication
Changes made using STcontroller will be
immediately reflected in the unit’s operation;
no Model 348 reboot is required. Each time
a change is made the eight buttons on the
Model 348’s front panel will flash orange in
a distinctive pattern to indicate that a com-
mand from STcontroller has been received.
General Menu Page
The following configuration selections are
available in the General menu selections
tab:
Microphone Input – Headset Mic Power
Choices are Enabled and Not Enabled (box
checked or not).
A headset can be connected by way of
a 5-pin female XLR connector, labeled
Headset A, or a 3.5 mm 4-conductor TRRS
jack, labeled Headset B. Enable the headset
microphone power check box if the con-
nected headset has an electret microphone
which requires a source of low-voltage DC
for operation. In virtually all cases gaming
or computer headsets that use a 3.5 mm
TRRS plug will require microphone power.
Most broadcast headsets that terminate on
a 5-pin male XLR connector will incorporate
a dynamic (non-powered) microphone. In
this case do not enable headset microphone
power. The on/off status of the headset
microphone power is displayed by way of
an LED, red in color, that is located on the
Model 348’s back panel below the Headset
A connector.
Note that the Model 348 cannot supply P12
or P48 phantom power that may be required
by balanced condenser (capacitor) micro-
phones. This should not pose an issue as
phantom-powered microphones are essen-
tially never associated with communications-
or intercom-style headsets that would be
used for Model 348 applications.

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Microphone Input – Headset Mic Gain
Choices are 26 dB, 32 dB, 38 dB, 44 dB,
and 50 dB.
To match the requirements of a microphone
associated with a headset, the gain of the
microphone preamplifier can be selected
from among five choices. The selected gain
is applied no matter if the headset is con-
nected using the Headset A or the Headset
B connector. The compressor active LED,
located below the Headset A connector, can
act as a guide when setting the microphone
preamplifier gain. When a voice signal at
a normal level is present on the connected
headset’s microphone the compressor ac-
tive LED should light intermittently. If, for
example, it rarely lights and the gain is set to
38 dB, it might be a good idea to change the
setting to 44 dB. If the compressor LED is lit
fully during normal talking and the gain is set
for 44 dB or 50 dB, a change to one of the
lower values might be warranted. There’s no
“hard and fast” rule as to which gain setting
is appropriate. But unless otherwise indicat-
ed, 38 dB is typically a good initial choice for
a headset that uses a dynamic microphone
while 32 dB would be appropriate for a head-
set that includes an electret microphone.
Microphone Input – Gooseneck Mic Gain
Choices are 12 dB, 18 dB, 24 dB, 30 dB,
and 36 dB.
When the gooseneck microphone is selected
as the Model 348’s active microphone input
source the gain of the microphone pream-
plifier will operate from among five configu-
rable choices. The compressor active LED,
located adjacent to the Headset A connector,
can act as a guide when setting the goose-
neck preamp gain. When a voice signal at a
normal level is presented to the gooseneck
microphone the compressor active LED
should light intermittently. If, for example,
the LED rarely lights and the gain is set to
18 dB, it might be a good idea to change the
setting to 24 dB or 30 dB. If the compressor
LED is lit fully during normal talking and the
gain is set for 30 or 36 dB, a change to one
of the lower values might be warranted.
Headset – Sidetone Level
Choices are Off, Low, Medium Low,
Medium, Medium High, and High.
As a user confidence signal, audio from the
selected microphone source can be routed
to the left and right headphone channels of
the headset interface. Sidetone audio can be
present whenever an applicable button func-
tion is active on any or all of the unit’s eight
channels. An applicable function is one that
uses either the headset or the gooseneck
microphone. These include Talk, Talk with
18 kHz Tone, and IFB. There is no definitive
sidetone level setting. One that provides the
user with a sufficient amount of their own
talk audio such that they are comfortable
should be sufficient.
Headset – Dim
Choices are 0 dB, 6 dB, 12 dB, and 18 dB.
This headset dim function allows the output
of the two headset output channels to be
“dimmed” (attenuated or reduced in level)
in certain circumstances. The function is
provided for special applications where the
headset’s left and right headphone outputs
are connected to an external amplifier or set
of amplified speakers. Normally when a talk
function is active on one or a combination
of the eight channels the level of the head-
set’s headphone output channels would not
change. As such, the default dim value has
been selected to be 0 dB. But if an adapter
cable was fabricated and the headset’s
headphone output channels were connected
to audio playback devices that presented

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MODEL 348
INTERCOM STATION
audio energy in the same physical vicinity as
the active microphone then acoustic feedback
is possible. To prevent this from happening
selecting a dim configuration of 6, 12, or 18
dB might be desirable.
Speaker – Source
Choices are Off, Monitor A, and Monitor B.
The Model 348 includes an internal loud-
speaker of which an audio source can be se-
lected from the two audio “mix” buses that are
named Monitor A or Monitor B. These buses
contain audio content that is specified in the
individual configuration choices for the eight
audio input channels. The speaker can be
designated to monitor either of these buses
or to not be active.
Speaker – Dim
Choices are 0 dB, 6 dB, 12 dB, and 18 dB.
The output level of the Model 348’s internal
loudspeaker will be automatically “dimmed”
(attenuated or reduced) whenever a talk
or IFB function is active on any of the eight
channels. This will help prevent audio from
the loudspeaker from interfering with the
operation of the selected microphone. In-
terference could be in the form of unwanted
audio content or even acoustical feedback.
It’s typical for a user who listens at a higher
output level to select a dim value that pro-
vides more reduction. In almost all cases a
selection of other than 0 dB (no dim) would
be appropriate.
Dante Monitor Outputs – Mode
Choices are Off, Pre-Fader, and Post-Fader.
The Model 348 provides two Dante transmit-
ter (output) channels, Monitor A and Monitor
B, that are intended for use by other pieces
of equipment such as amplified speakers,
audio consoles, and matrix intercom systems.
These two channels can be configured as a
group to function from among three choices.
Off: In this mode the two Dante monitor
output channels, Monitor A and Monitor B,
will not have audio present on them. The
Dante Controller software application will still
indicate that the channels are present but no
audio will be routed to them from the Model
348’s circuitry.
Pre-Fader: In this mode the audio level and
on/off status of Dante monitor output chan-
nels will not be impacted by the Model 348’s
monitor output rotary encoder. To clarify,
neither level adjustment or on/off control will
occur. This mode is appropriate when the
monitor output channels are going to be uti-
lized by devices that incorporate, if required,
level control and/or signal muting capability.
Post-Fader: In this mode the audio level and
on/off status of Dante output channels Moni-
tor A and Monitor B will follow the action of
the Model 348’s monitor output rotary encod-
er. This mode is applicable if the device or
devices utilizing the Dante monitor outputs
require that the level of the source signals
be adjusted and/or muted using the Model
348’s resources.
Dante Monitor Outputs – Dim
Choices are 0 dB, 6 dB, 12 dB, and 18 dB.
When a talk or IFB function is active the
Model 348 will invoke a dim (attenuation)
function. This is designed to help achieve
maximum intelligibility and minimize the
chance of acoustic feedback when loud-
speakers are associated with either or both
Dante monitor outputs Monitor A or Moni-
tor B. A dim setting of 0 dB means that the
signal level on the Dante monitor outputs will
remain unchanged. (The signal will be at-
tenuated by 0 dB which is no attenuation!)

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System – Level Control Position Display
Choices are Off and On.
For user assistance the orange LEDs con-
tained within the eight pushbutton switches
can be utilized in a “bar graph” format to give
a general indication of the settings of the ten
rotary encoders. If enabled, whenever the
setting of a rotary encoder is changed the
LEDs eight buttons will momentarily light. In
most cases it would be advantageous to en-
able this function.
System – Signal Present Display
Choices are Off and On.
The top surface of the ten rotary encoders
can light as an indication of the level of the
audio associated with a specific encoder
and related function. This is accomplished
by the incorporation of red, green, and blue
LEDs located within each encoder. The knob
will light green when signal levels are in the
normal range, yellow when the signal level is
greater than normal, and red when the sig-
nal level is at risk of degrading audio perfor-
mance. Note that even if the Signal Present
Display function is disabled (Off) the rotary
encoders will still display their normal and
muted state using LED illumination.
System – LED Intensity
Choices are Low and High.
The eight pushbutton switches, ten rotary
encoders, and mic source selection func-
tion have LED indicators associated with
them. The LED intensity configuration choice
allows the overall intensity of theses LEDs
to be selected. Typically, deciding which
choice, low or high, is optimal will depend on
the amount of ambient light present where
the Model 348 is located.
System – Headset and Monitor Outputs
Follow Mic Source
Choices are Off and On.
This function allows the muted/unmuted
state of the headset’s headphone outputs,
the Dante monitor outputs (when configured
for post-fader), and the speaker output to
automatically be determined by the user’s
choice of which microphone is active. This
is a sophisticated function that can prove
useful for users who are frequently switch-
ing between the headset microphone and
the gooseneck microphone. When the func-
tion is enabled, whenever the microphone
source selection changes from gooseneck
to headset the Dante monitor output chan-
nels (only when configured for post-fader)
and the speaker will mute. And whenever
the microphone source selection changes
from headset to gooseneck the headset’s
headphone outputs will mute. This helps to
ensure that unwanted audio isn’t present as
a specific microphone source is selected.
System – Hot Mic
Choices are Off and On.
A Dante transmitter (output) channel is
available which provides a hot mic (always
active) function. This can be very useful but
has the potential for abuse. This configura-
tion choice ensures that a hot mic signal is
only available when an application warrants
it.
Note that even if the hot mic output is dis-
abled the channel will appear in the Dante
Controller. But in this case no signal would
be present on the channel.
System – Monitor A Call Tone Level
Choices are Off, Low, Medium, and High.
The Model 348 is capable of generating an
audible alerting signal when a call signal is
detected on a channel that is assigned to

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MODEL 348
INTERCOM STATION
the Monitor A audio bus. This signal consists
of repeating sequences of three short bursts
of sine wave audio that are output by way of
the speaker. The level range can be selected
from among three choices as well as being
selected for off (muted).
System – Monitor B Call Tone Level
Choices are Off, Low, Medium, and High.
The Model 348 is capable of generating an
audible alerting signal when a call signal is
detected on a channel that is assigned to the
Monitor B audio bus. This signal consists of
repeating sequences of three short bursts
of sine wave audio that are output by way of
the speaker. The level range can be selected
from among three choices as well as being
selected for off (muted).
Channel Specific Menu Page
The following configuration selections apply
individually to Channels 1-8. They are avail-
able in each Channel Specific menu tab:
Button Mode
Choices are Momentary, Latching, and
Hybrid.
The manner in which a button functions can
be configured from among three choices.
Momentary: If this mode is selected a but-
ton’s function will normally be inactive and the
LEDs associated with the button will not be
lit. Whenever a button is pressed the associ-
ated function will become active and its green
LED will light.
Latching: If this mode is selected the button’s
function will alternate between its active
and inactive states whenever the button is
pressed. The button’s green LED will be lit
whenever the associated function is active.
Upon Model 348 power up the button will be
in its inactive state and its LEDs will not be lit.
Hybrid: This mode is a combination of the
Momentary and Latching modes. It’s similar
to the way in which pushbutton switches
often function on user stations associated
with broadcast or production intercom sys-
tems. If the button is pressed and held the
associated function will be active. It will stay
active until the button is released. If the but-
ton is momentarily “tapped” the status of the
function will change, either from inactive-to-
active or from active-to-inactive. The button’s
green LED will be lit whenever the function
is active. Upon Model 348 power up the but-
ton will be in its inactive state and its LEDs
will not be lit.
Button Function
Choices are Talk, Talk with 18 kHz Tone,
All Talk, Call, IFB, All IFB, 18 kHz Tone,
20 kHz Tone, and Disabled.
Talk: In this mode whenever the function is
active microphone audio will be sent out the
associated Dante audio output (transmitter)
channel. This mode will typically be used
as part of an intercom or stage announce
(SA) implementation. The sidetone function
will be active whenever the talk function is
active.
Talk with 18 kHz Tone: This mode is simi-
lar to the Talk mode except that an 18 kHz
sine wave tone is added (summed) with the
microphone audio. It is intended for use in
REMI/At-Home applications where a “pilot
tone” needs to be sent along with talk audio.
This is specifically provided for use with the
tone-activated (“TOX”) IFB function in the
Studio Technologies’ Model 5422 Dante
Intercom Audio Engine product. The sidet-
one function will be active whenever the
Talk with 18 kHz Tone function is active
All Talk: In this mode the associated button
will activate all Model 348 channels that are
configured for Talk or Talk with 18 kHz Tone.

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Call: In this mode pressing the associated
button will cause a 20 kHz sine wave call
tone to be sent out any Model 348 channels
that are both configured for the Talk or the
Talk with 18 kHz Tone modes and are cur-
rently active.
IFB: In this mode the Model 348 channel will
be used to create a broadcast-type interrupt-
ed foldback (IFB) or talent cue source. When
the function is not active audio from the cor-
responding Dante IFB program audio input
channel will be routed to the corresponding
Dante output channel. When the function is
active the microphone (interrupt) audio will be
combined with the IFB program audio source.
The IFB program audio source will be attenu-
ated, fully muted, or not changed, following
the IFB Program Dim Level configuration.
The sidetone function will be active whenever
the IFB function is active
All IFB: In this mode pressing the associated
button will cause all the channels configured
for IFB to become active. Note that an audio
source routed to the associated IFB program
input will be continually routed to the chan-
nel’s associated audio output. This would
typically be the non-interrupt audio source.
This is provided such that a timing match can
be made between the IFB and non-interrupt
output channels.
18 kHz Tone: In this mode an 18 kHz sine
wave tone will be sent out the associated
Dante output (transmitter) channel. This func-
tion can be useful for triggering other func-
tions associated with devices such as the
Model 5422 Dante Intercom Audio Engine.
20 kHz Tone: In this mode a 20 kHz sine
wave tone will be sent out the associated
Dante output (transmitter) channel. This func-
tion can be useful for triggering other func-
tions associated with devices such as the
Model 5422 Dante Intercom Audio Engine.
Disabled: In this mode the button will not
perform a function. Pressing it will cause the
button’s red LED to flash, indicating that it
has been disabled.
IFB Program Dim
Choices are 0 dB, 5 dB, 10 dB, 15 dB,
20 dB, and Full Mute.
This value determines the amount of attenu-
ation that will be applied to the Dante pro-
gram audio input (receive) source when the
IFB function is active for this channel. 0 dB
will configure the channel to have no change
in program audio level. The talk audio will
simply be added (summed) with the program
audio. When Full Mute is selected the IFB
program audio source level will fully attenu-
ate and be replaced by the talk (interrupt)
audio. In most broadcast applications the
default value of 15 dB will be appropriate.
Headset Routing
Choices are Off, Left, Right, and Left and
Right.
The Dante input (receiver) audio associated
with a Model 348 channel can be monitored
using the headset’s headphone outputs. The
destination channel(s) can be configured as
desired.
Off: In this mode the input audio will not be
sent to either the left or right headphone
output channels.
Left: In this mode the input audio will be sent
to only the left headphone output channel.
Right: In this mode the input audio will be
sent to only the right headphone output
channel.
Left and Right: In this mode the input audio
will be sent to both the left and right head-
phone output channels.

Model 348 User Guide Issue Preliminary 2, November 2019
Studio Technologies, Inc. Page 15
MODEL 348
INTERCOM STATION
Monitor Routing
Choices are Off, Monitor A, Monitor B, and
Monitor A and B.
The Dante input (receiver) audio associated
with a Model 348 channel can be monitored
using the Dante monitor output channels.
The destination channel(s) can be config-
ured as desired.
Off: In this mode the input audio will not be
sent to either of the monitor output channels.
Monitor A: In this mode the input audio will
be sent only to the Monitor A output channel.
Monitor B: In this mode the input audio will
be sent only to the Monitor B output channel.
Monitor A and B: In this mode the input au-
dio will be sent to both the Monitor A and the
Monitor B output channels.
Call Indication
Choices are Off, Visual Only, and Visual
and Audible.
A visual and audible indication can be
provided whenever a call signal has been
detected on a Model 348 channel. The visual
indication is provided by way of the pushbut-
ton’s LED indicators. The audible indication
is provided by way of the Model 348’s inter-
nal loudspeaker and, if configured appropri-
ately, Dante monitor outputs.
Off: In this mode no visual or audible indica-
tion in response to a call signal will be
generated.
Visual Only: In this mode when a call signal
is detected the orange LED in the associ-
ated pushbutton will flash on and off.
Visual and Audible: In this mode when a call
signal is detected the orange LED in the
associated pushbutton will flash on and off.
In addition, sequences of audio tones will be
output by the monitor loudspeaker. The audio
tones will also be sent to the Monitor A and/or
Monitor B Dante output if the channel’s audio
input has been so configured.
Operation
At this point all connections and configura-
tion steps should have been completed and
everything should be ready for Model 348
operation to commence. In most cases an
Ethernet connection with Power-over-Ether-
net (PoE) capability will have been made to
the primary Ethernet connector. Alternately, a
source of 12 volts DC may have been con-
nected to provide power for the Model 348.
A stereo or monaural headset will typically
be interfaced using either the Headset A
or Headset B connector. A gooseneck mi-
crophone may have been installed into the
bushing/connector assembly on the top of the
Model 348’s enclosure.
Using the Studio Technologies’ STcontroller
software application the Model 348’s operat-
ing configuration should have been selected
to meet the needs of the specific application.
An extensive range of configurable parame-
ters are available, making the way in which a
specific Model 348 operates be quite unique.
Using the Dante Controller software applica-
tion the Model 348’s network interface and
audio channel configuration should have
been made. In this way, the operational char-
acteristics of the unit’s two Ethernet interfac-
es will have been selected. In addition, some
or all of the eleven Dante audio output chan-
nels (Dante transmitter channels) and sixteen
Dante audio input channels (Dante receiver
channels) will have been routed, by way of
Dante “subscriptions,” to the receiver and
transmitter channels on associated Dante-
enabled equipment.

Issue Preliminary 2, November 2019 Model 348 User Guide
Page 16 Studio Technologies, Inc.
MODEL 348
INTERCOM STATION
Eight of the Dante audio output channels are
associated with the functioning of the eight
pushbutton switches. Two additional Dante
audio output channels are specified as
monitor outputs. And the final Dante output
channel provides a Hot Mic output function.
Eight of the Dante audio input channels are
assigned to the monitor section. Each of
these inputs has an associated rotary en-
coder to adjust its signal level. Eight more of
the Dante audio input channels serve as IFB
program inputs. These are used in conjunc-
tion with the eight pushbutton switches when
they are configured for IFB operation.
Initial Operation
The Model 348 will start to function as soon
as a Power-over-Ethernet (PoE) or a 12
volts DC power source is connected. How-
ever, it may take up to 30 or 40 seconds
for full operation to commence. Upon initial
power up the various status LEDs, located
on the back panel, and the mic source, ro-
tary encoder, and pushbutton LEDs on front
panel will light as the internal processors,
Ethernet network, and Dante connections
begin to function. The various LEDs will then
become operational, displaying the status of
their associated functions.
Power Status LEDs
An LED labeled PoE is located below the pri-
mary Ethernet connector on the Model 348’s
back panel. It will light green if an Ethernet
signal that is providing PoE power is con-
nected. An LED labeled DC is located below
the 4-pin XLR connector that is provided for
connection to a DC power source. It will light
green if a source of 10 to 18 volts DC is con-
nected. If both the PoE and DC LEDs are
lit then the PoE Ethernet connection will be
providing power to operate the Model 348.
The DC power supply will be ready as a “hot
standby” should the PoE source fail.
Ethernet Status LEDs
A total of four Ethernet status LEDs are locat-
ed below the two etherCON RJ45 connectors
on the Model 348’s back panel. A LINK ACT
LED will light green whenever an active con-
nection to an Ethernet network has been es-
tablished. It will flash in response to Ethernet
data packet activity on that interface. A GbE
LED will light orange when a gigabit Ethernet
connection is present on that interface.
Dante Status LEDs
The SYS and SYNC LEDs, also located on
the back panel, display the operating status
of the Dante interface and its associated net-
work activity. After lighting red and green as
part of the power-up sequence the SYS LED
will light red to indicate that the Dante inter-
face is not ready. After a short interval it will
light green to indicate that it is ready to pass
data with another Dante device. The SYNC
LED will also be part of the power-up se-
quence and will light red when the Model 348
is not synchronized with a Dante network. It
will light solid green when the Model 348 is
synchronized with a Dante network and an
external clock source (timing reference) is
being received. It will slowly flash green when
this specific Model 348 is part of a Dante net-
work and is serving as the clock master. It’s
possible that up to 30 or 40 seconds may be
required for the SYNC LED to reach its final
state.
How to Identify a Specific
Model 348
Functions within the Dante Controller and
STcontroller software applications allow spe-
cific Model 348 units to be identified. Each
application provides an “eyeball” icon that
when clicked will activate the Identify func-
tion. When Identify is selected it will send a
command to a specific Model 348 unit. On
that unit the red LEDs associated with the

Model 348 User Guide Issue Preliminary 2, November 2019
Studio Technologies, Inc. Page 17
MODEL 348
INTERCOM STATION
gain setting should be reduced. Conversely,
if the COMP LED almost never lights when
normal talking is taking place it’s possible that
changing the gain to a higher value would be
beneficial. Note that due to the design of the
circuitry the compressor active LED will func-
tion whether or not the main or talkback func-
tions are active.
LED Intensity
On the Model 348’s front panel there are LED
indicators associated with the eight channel
pushbutton switches, the mic source status
display, and the ten rotary encoders. Using
the STcontroller application the intensity of
these LEDs, as a group, can be configured
from among two choices, low or high. If during
operation the LED intensity isn’t perceived to
be optimal the configuration choice in ST-
controller should be checked and revised if
necessary. In most cases the default intensity,
high, will be applicable. However, the low LED
intensity configuration choice may be superior
in applications where the ambient light in the
Model 348’s location is also low.
Mic Source Selection
A small, round pushbutton switch located on
the upper-left side of the front panel is used
to select which microphone source is active.
This audio source will be used as needed by
the Model 348’s talk, sidetone, and IFB func-
tions. The mic source choices are Headset
and Gooseneck. Two green LEDs, adjacent to
the pushbutton switch, indicate which micro-
phone source is currently active. A Model 348
power-down/power-up cycle will return the
microphone source to its last selection.
A system configuration choice in STcontroller
allows the microphone source selection to
impact the on/off status of the headset’s head-
phone outputs and the monitor output chan-
nels. Named Follow Mic Source, this selection
is provided to assist users who frequently
eight pushbutton switches will “flash” in a
unique sequence four times; the actual on/off
status of the buttons will not change. In ad-
dition, the LINK ACT and GbE status LEDs,
located directly below the two RJ45 connec-
tors on the back panel, will slowly flash. After
a few seconds the LED identification patterns
will cease and normal Model 348 pushbutton
LED, and Ethernet status LED operation will
resume.
Headset Microphone Power
Status LED
An LED indicator is located on the back pan-
el adjacent to the Headset A connector. It is
labeled MIC PWR and will light red whenever
the headset’s microphone electret power
source is active and providing low-voltage
DC power to the microphone connections on
the Headset A and Headset B connectors.
Compressor Active LED and
Mic Preamp Gain
An LED indicator, orange in color, is located
on the back panel adjacent to the Headset A
connector. It is labeled COMP and displays
the status of the microphone audio compres-
sor function. This function controls the dy-
namic range of the audio signal associated
with the selected microphone input source.
(This will be either the headset’s microphone
or the gooseneck microphone.) The com-
pressor LED will light whenever the input
level from the active microphone, along with
the configured microphone preamplifier gain,
is such that the dynamic range of the signal
is being actively controlled. It’s perfectly ac-
ceptable for this LED to light intermittently
whenever a user is talking at a normal voice
level into an associated microphone. But if
the COMP LED lights solid while a user is
talking at a normal voice level this will typical-
ly indicate that the microphone preamplifier

Issue Preliminary 2, November 2019 Model 348 User Guide
Page 18 Studio Technologies, Inc.
MODEL 348
INTERCOM STATION
change between using the headset’s mi-
crophone and the gooseneck microphone.
The default configuration is for this feature
to be disabled (Off). When this configura-
tion choice is enabled (On) and Gooseneck
is selected as the microphone source the
headset’s headphone outputs will mute.
When the headset’s microphone is selected
as the source the monitor outputs and as-
sociated loudspeaker will also mute. In both
cases the mute state that was automatically
enabled can be overridden by pressing the
knob on the applicable rotary encoder.
Each microphone source, headset and
gooseneck, has an independent preamplifier
gain configuration parameter which is ac-
cessible by way of the STcontroller software
application. If switching between the two
microphone sources results in a greatly dif-
ferent overall microphone audio levels then
the configuration choice for the microphone
preamplifier gains should be reviewed and
revised as appropriate.
Hot Mic Output
A Dante output channel has been designat-
ed as a hot mic output. This output can be
enabled or disabled using the STcontroller
software application. The default setting is
Disabled. When enabled the selected micro-
phone source, headset or gooseneck, will be
permanently connected to the Hot Mic Dante
output channel. No pushbutton or encoder
operation is required for the audio associ-
ated with the selected microphone source to
be active on the Hot Mic Dante output. This
can be a useful feature but it’s important that
user be made aware that there is no means
of turning off (“muting”) this output. They
must assume that other personnel will be
continually monitoring audio associated with
their selected microphone.
Button Action
The action of each of the eight pushbut-
ton switches can be individually configured
using STcontroller. There are three button
action choices available and a description of
them follows:
Momentary
If this mode is selected the pushbutton’s as-
sociated function will become active when-
ever the button is pressed and held. When
the function is active the pushbutton’s green
LEDs will be lit.
Latching
If this mode is selected the function associ-
ated with the button will alternate between
its active and inactive states whenever
the pushbutton is momentarily pressed
(“tapped”). The pushbutton’s green LEDs will
be lit whenever the function is active. Upon
Model 348 power up the button’s associated
function will be in its inactive state.
Hybrid
This mode is a combination of the momen-
tary and latching actions. If the pushbutton
is pressed and held the associated function
will become active until the pushbutton is
released. If the pushbutton is momentarily
pressed (“tapped”) the function will change
state. The pushbutton’s green LEDs will be
lit whenever the function is active. Upon
Model 348 power up the pushbutton’s asso-
ciated function will be in its inactive state.
Button Function
The button function configuration is used to
select the overall manner in which a specific
pushbutton channel operates. Each push-
button can be independently configured from
among nine choices. A careful study of how
each of these choice’s function will highlight
the variety of applications a Model 348 can
support. While the product’s title includes the

Model 348 User Guide Issue Preliminary 2, November 2019
Studio Technologies, Inc. Page 19
MODEL 348
INTERCOM STATION
Call
When a button function has been configured
for Call and the pushbutton is pressed or the
function is active then all other pushbuttons
that are both configured for Talk or Talk with
18 kHz and are active will have a 20 kHz sine
wave tone at a level of –20 dBFS added to
their associated Dante output channels. The
LED in the pushbutton configured for Call will
light orange whenever the function is active.
The buttons that are configured for Talk or Talk
with 18 kHz that are active will flash orange.
The associated Dante output channel will not
be utilized, nor will the associated Dante IFB
program input channel.
IFB
When a button function has been configured
for IFB a broadcast-type interrupted foldback
(IFB), also referred to an interruptible foldback
or a talent cue signal, will be created. When
the pushbutton is not pressed or active the
associated Dante IFB program input source
will be connected to the associated Dante
output channel. The Dante IFB program input
source is connected to the Dante output chan-
nel at unity level (no gain or attenuation will be
applied to the signal). When the pushbutton
is pressed or the function is active then two
things will occur. The first is that the Dante IFB
program input source will be acted on follow-
ing the configuration for the IFB program dim
value. This will result in the signal level either
staying the same, dropping in level (being at-
tenuated) by one of four values, or completely
muting. The second action is that the selected
microphone source will be added (summed)
with the Dante IFB program input source and
then routed to the associated Dante output
channel. The pushbutton will light green when
the function is active.
The IFB function creates a talent cueing signal
that is sometimes referred to as Interrupt, Pro-
gram with Interrupt, or Program + Interrupt.
text “Intercom Station,” that far from cov-
ers all the applications in which the unit can
provide value.
Talk
When a button function has been configured
for Talk and the pushbutton is pressed or the
function is active then audio from the se-
lected microphone source will be connected
to the associated Dante output channel. The
LED in the pushbutton switch will light green
whenever the function is active. When the
pushbutton is not pressed nor currently ac-
tive no audio will be present on the associ-
ated Dante output channel. The associated
Dante IFB program input channel will not be
utilized.
Talk with 18 kHz Tone
When a button function has been configured
for Talk with 18 kHz Tone and the pushbut-
ton is pressed or the function is active then
audio from the selected microphone source,
mixed with an 18 kHz sine wave tone at a
level of –20 dBFS, will be connected to the
associated Dante output channel. The LED
in the pushbutton switch will light green
whenever the function is active. When the
pushbutton is not pressed nor the function is
active no audio (voice or tone) will be pres-
ent on the associated Dante output channel.
The associated Dante IFB program input
channel will not be utilized.
All Talk
When a button function has been configured
for All Talk and the pushbutton is pressed
or the function is active then all other but-
tons that are configured for Talk or Talk with
18 kHz will become active. The LED in the
pushbuttons configured for All Talk will light
green whenever the function is active. The
associated Dante output channel will not be
utilized, nor will the associated Dante IFB
program input channel.

Issue Preliminary 2, November 2019 Model 348 User Guide
Page 20 Studio Technologies, Inc.
MODEL 348
INTERCOM STATION
to the associated Dante output channel. No
voice or IFB program audio is connected to
the associated Dante output channel.
20 kHz Tone
When a button function has been configured
for 20 kHz Tone the operation is very simple.
When the pushbutton is pressed or the func-
tion is active a 20 kHz sine wave tone at –20
dBFS is connected to the associated Dante
output channel. No voice or IFB program au-
dio is connected to the Dante output channel.
Disabled
When a button function has been configured
for Disabled no audio action will take place.
If the pushbutton is pressed it will flash red to
indicate that this specific button is disabled.
No voice, tone, or IFB program audio is con-
nected to the Dante output channel.
Using the Rotary Encoders
On the front panel of the Model 348 there are
ten rotary encoders. Eight of the rotary en-
coders are located above the channel push-
button switches. They are associated with the
Dante audio input channels. A single rotary
encoder is associated with the level of the
headset’s headphone outputs. And finally, a
rotary encoder is associated with the monitor
section, impacting the internal loudspeaker
and, if configured for post-fader, the two
Dante monitor output channels. Each encod-
er has 24 steps (“clicks” or “detents”) for each
360 degrees of rotation. Turning an encoder
knob clockwise by 1 and 1/3 rotations (32
steps or 480 degrees) is required to change
from audio minimum to audio maximum. (As
expected, the same action occurs in reverse:
when rotating an encoder counterclockwise
by 32 steps the audio level will change from
maximum to minimum.) Pressing on the top
of an encoder’s knob will activate a momen-
tary switch function that is used to mute the
associate audio signal(s).
The selected microphone source (headset or
gooseneck) serves as the interrupt source.
The Dante IFB program input signal is con-
sidered to be the program audio source.
Note that there is no means provided within
the Model 348 to adjust the level of the IFB
program input source. This should not be
considered an operational limitation as typi-
cally an audio console will provide the pro-
gram audio source at a nominal line level. As
such, any needed adjustment of the signal
level can be performed on the console.
All IFB
When a button function has been configured
for All IFB and the pushbutton is pressed or
the function is active then all of the other but-
tons configured for IFB will become active.
The LED in the pushbutton will light green
whenever the function is active. The Dante
IFB program audio input will continuously be
connected to the associated Dante output
channel. This is provided as a Program or
Program Only audio signal for use in a dual-
channel IFB implementation. Typically, the
first channel of a dual-channel IFB signal or
“feed” is referred to as Interrupt or Program
with Interrupt while the second channel is
referred to as Program or Program Only. Us-
ing this Dante input-to-output loop-through
arrangement can be valuable as any latency
(time delay) that occurs within the Model
348’s IFB function will be matched in the All
IFB signal path. In this way, the Model 348’s
audio latency will essentially be matched in
the program with interrupt and program-only
audio paths.
18 kHz Tone
When a button function has been config-
ured for 18 kHz Tone the channel’s opera-
tion is very simple. When the pushbutton is
pressed or the function is active an 18 kHz
sine wave tone at –20 dBFS is connected