Studio Technologies 348 User manual

Copyright © 2021 by Studio Technologies, Inc., all rights reserved
studio-tech.com
User Guide
Issue 5, May 2021
This User Guide is applicable for serial numbers
M348-00251 and later with Main Firmware version 2.01 and later
and STcontroller application version 3.03.00 and later.
50291-0521 Issue 5
Model 348 Intercom Station

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Model 348 User Guide Issue 5, May 2021
Studio Technologies, Inc. Page 3
MODEL 348
INTERCOM STATION
Table of Contents
Revision History ...................................................................... 4
Introduction ............................................................................... 5
Getting Started ......................................................................... 8
Dante Configuration ................................................................ 11
Model 348 Configuration ......................................................... 13
Operation ................................................................................. 21
Technical Notes ....................................................................... 31
Specifications .......................................................................... 36
Appendix A–STcontroller Default Configuration Values ........... 38
Appendix B–3-Pin Header Connector Details .......................... 39

Issue 5, May 2021 Model 348 User Guide
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MODEL 348
INTERCOM STATION
Revision History
Issue 5, May 2021:
• Documents that support is now included for two remote control inputs.
• Documents that a Dante receiver (input) channel can be used as a microphone input source.
(In conjunction with this, Dante receiver (input) channel 16 renamed from “IFB Pgm 8” to
“Aux In.”)
• Documents new Talk with Quindar Tones button mode.
• Miscellaneous corrections and improvements.
Issue 4, April 2021:
• Documents that unit now enumerates itself as a class 3 PoE device.
Issue 3, February 2021:
• Clarifies the Microphone Input – Source function in STcontroller.
Issue 2, August 2020:
• Corrects errors in Issue 1.
Issue 1, January 2020:
• Initial release of complete document.

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MODEL 348
INTERCOM STATION
Introduction
The Model 348 Intercom Station provides
eight independent talk and listen channels
that are compatible with Dante® audio-over-
Ethernet networks. The desktop unit is de-
signed to serve as an audio control center for
production and support personnel in numer-
ous applications including on-air television
sports and news broadcasting, live events,
theater, industrial, aerospace, and corporate
AV. The Model 348’s channels can be part of
virtual “party-lines” created with other compat-
ible devices or be used directly in point-to-
point intercom implementations. The range of
resources makes it simple to use the Model
348 locally, or as part of a REMI or “At-Home”
geographically diverse implementation. In
addition to intercom applications, the unit
can create multiple independent IFB (talent
cue) channels. Other applications may benefit
from the Model 348 user’s ability to easily cre-
ate monitor mixes from the eight input audio
channels. This makes the unit a viable choice
for listen-only scenarios.
Over a standard IP network, multiple Model
348 units can be used in party-line (PL) in-
tercom applications with help from external
Dante-enabled audio devices such as the
Studio Technologies’ Model 5421 or Model
5422A Dante Intercom Audio Engine. Model
348 units can also be used “point-to-point”
or interfaced with Dante-compatible matrix
intercom systems. The Model 348 includes
two Neutrik etherCON RJ45 jacks which allow
interfacing with single or redundant Dante
Ethernet networks. The primary network con-
nection can provide power to the unit using
standard Power-over-Ethernet (PoE). It can
also be powered using a 12 volts DC source
that is connected using a broadcast-standard
4-pin XLR connector.
The Model 348 supports connection of a
broadcast- or intercom-style headset that use
a dynamic or electret (DC powered) micro-
phone. The unit provides both a 5-pin female
XLR and a 3.5 mm TRRS connector allow-
ing for a traditional “pro” or a contemporary
gaming headset to be utilized. In addition,
the Studio Technologies’ GME-3-12 electret
gooseneck microphone can be directly con-
nected using the 1/4-inch jack located on the
top of the unit’s enclosure. A low-noise micro-
phone preamplifier and associated voltage-
controlled-amplifier (VCA) dynamics controller
(compressor) ensures excellent headset and
gooseneck microphone audio quality while
minimizing the chance of signal overload.
Figure 1. Model 348 Intercom Station front and back views

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INTERCOM STATION
A Dante receiver (input) channel can also be
used as the talk audio source. This was specif-
ically included to allow two Model 348 units to
“work” together to support more than eight talk
channels. A pushbutton switch allows users
to directly select the active talk audio source.
Choices include the headset mic, the goose-
neck mic, or the Dante Aux In receiver (input)
channel.
All Model 348 operating features are config-
ured using the STcontroller software applica-
tion. An extensive set of parameters allows
the unit’s functions to be tailored to meet the
needs of many applications. STcontroller is
available, free of charge, from the Studio
Technologies’ website. Versions are available
that are compatible with the Windows® and
macOS® operating systems. STcontroller is a
fast and simple means of configuring, revising,
saving, and loading a unit’s operating param-
eters.
The Model 348’s front panel includes eight
rotary controls (“encoders”) which are used
to adjust the level of the eight Dante monitor
input signal sources. Using RGB (red-green-
blue) LEDs, the knob of each encoder is illu-
minated and can display if a channel is muted,
indicate if a signal is present on the associ-
ated audio input, and light when an in-band
(20 kHz tone) call signal is detected. The user
can monitor the Dante audio inputs by means
of a headset, a built-in speaker, or two Dante
transmitter (output) channels. Two additional
rotary encoders are used to control the overall
audio level and on or off (mute) status of the
signals being sent to the headset and speaker
outputs. A modern class-D amplifier integrated
circuit drives the speaker efficiently while pre-
serving audio fidelity.
Extensive configuration choices allow the
operation of the eight pushbutton switches and
associated output channels to be optimized
to meet the needs of an extensive range of
specialized applications. They can be inde-
pendently configured for talk (intercom), IFB
(talent cue), call signal (20 kHz tone), and
other related actions. The buttons can also be
configured to provide an “all-call” action asso-
ciated with the talk and IFB functions.
A special button configuration mode supports
the generation of talk channels that include
Quindar Tones. These are short-duration
“intro” and “outro” audio signals that were
traditionally used in space programs to control
the on and off status of transmitters. In recent
years these tones have taken on the function
of providing an audible indication of when
Capsule Communicator (CapCom) transmis-
sions are taking place. These ubiquitous
“beeps” have become synonymous with
ground-to-astronaut communications.
For performance confirmation an integrated
sidetone function allows audio coming from the
active talk audio source to be returned to the
headset output. An audible alert, using the in-
ternal speaker, can be generated in response
to a call signal. Provision has been made such
that a technician can “customize” the Model
348’s hardware. Option kits, purchased sepa-
rately, can be added to support additional func-
tions. These include adding two remote control
inputs which can be configured to mimic the
action of talk buttons.
The Model 348’s compact enclosure has over-
all dimensions of 6.5 inches wide (16.5 cm),
2.5 inches high (6.4 cm), and 4.6 inches deep
(11.7 cm). Weighing 1.8 pounds (0.8 kg), the
enclosure is made of steel to provide some
“heft” to minimize the chance of inadvertent
movement. The Model 348’s main application
firmware can be updated using the USB port
on the back of the unit; the Dante firmware can
be updated via an Ethernet connection.

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Ethernet Data and PoE
The Model 348 connects to one or two local
area networks (LANs) by way of two twisted-
pair Ethernet interfaces. The 1000BASE-T
Gigabit Ethernet (GigE) interconnections are
made by way of Neutrik® etherCON RJ45
jacks. While compatible with standard RJ45
plugs, etherCON allows a ruggedized and
locking interconnection for harsh or high-
reliability environments. The two Ethernet
interfaces can be configured, using the Dante
Controller software applications, to serve in
Switched or Redundant modes.
The Model 348’s operating power can be
provided by way of the Primary-PoE Ethernet
interface using the 802.3af Power-over-
Ethernet (PoE) standard. PoE allows fast
and efficient interconnection with the associ-
ated data network. Alternately, an external
source of nominal 12 volts DC can be con-
nected to power the unit. If both are connect-
ed then PoE will be the active power source.
Dante Audio-over-Ethernet
Audio data is sent to and received from the
Model 348 using the Dante audio-over-Eth-
ernet media networking technology. As a
Dante-compliant device, the Model 348’s 11
Dante transmitter (output) audio channels and
16 Dante receiver (input) audio channels can
be assigned (routed or “subscribed”) using
the Dante Controller software application.
The Dante transmitter and receiver channels
support 32 Dante flows, 16 in each direction.
The digital audio’s bit depth is up to 32 with a
sample rate of 48 kHz. Bi-color LEDs, located
on the unit’s back panel, provide status indi-
cations of the Ethernet network and Dante
interface performance.
The Model 348 is compliant with the AES67
interoperability standard. In addition, the unit
is compatible with Audinate’s® Dante Domain
Manager™ (DDM) software application.
Audio Quality
The Model 348’s audio performance is com-
pletely “pro.” A low-noise, wide dynamic-range
microphone preamplifier and associated
voltage-controlled-amplifier (VCA) dynamics
controller (compressor) ensure that headset
and gooseneck microphone audio quality is
preserved and minimizes the chance of signal
overload. The output of the microphone pre-
amp and compressor is routed to an ana-
log-to-digital conversion (ADC) section that
supports sampling rates of 48 kHz. A Dante
receiver (input) channel can be used as an
alternate talk source.The selected talk audio
signal routes through a 32-bit microprocessor
and on to the Dante interface section where
it is packetized and prepared for transport
over Ethernet. A total of 11 Dante transmit-
ter (output) channels are provided: one each
associated with the unit’s eight channels, two
monitor output channels, and one hot mic
output channel.
Audio input signals arrive via 16 Dante re-
ceiver (input) channels and pass into the
Model 348’s 32-bit microprocessor. Eight
input channels are associated with the moni-
tor section while the other eight inputs are
used as program sources for the IFB (talent
cue) functions. One of the latter input sources
can also serve as a talk audio source. All
channel routing, headphone and monitor level
control, IFB creation, and sidetone functional-
ity is performed within the digital domain. This
provides flexibility, allows precise level con-
trol, and eliminates the need for analog audio
signals from having to pass through electro-
mechanical level controls. The audio signals
destined for the headphone and speaker
outputs are sent to high-performance digital-
to-analog converter circuitry and then on to
robust driver circuitry.

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Future Capabilities and
Firmware Updating
The Model 348 was designed so that its ca-
pabilities and performance can be easily en-
hanced in the future. A USB connector, located
on the unit’s back panel, allows the application
firmware (embedded software) to be updated
using a USB flash drive. The Model 348 uses
the Broadway™ integrated circuit from Audi-
nate to implement its Dante interface. The firm-
ware in this integrated circuit can be updated
via an Ethernet connection, helping to ensure
that its capabilities remain up to date.
Getting Started
What’s Included
Included in the shipping carton are a Model
348 Announcer’s Console and instructions on
how to obtain an electronic 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 exter-
nal 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,
many applications will utilize the Studio
Technologies’ GME-3-12 gooseneck micro-
phone which will be attached via the 1/4-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-PoE RJ45 jack is compatible
with Power-over-Ethernet (PoE). If desired, an
Ethernet connection made to the Secondary
Ethernet receptacle can provide access to a
Redundant Dante network. Or it can be utilized
as an active “loop through” connection associ-
ated 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 1/4-inch plug can be connected.
For special applications, the Model 348’s inter-
nal circuit boards contain 3-pin “header” con-
nectors that allow access to several functions.
In addition, there’s one spare connector loca-
tion on the Model 348’s back panel. A techni-
cian can add a connector and wire it to the
headers such that application-specific needs
can be supported. For example, two contact
closures can be interfaced to the Model 348’s
circuitry allowing external switches to activate
two of the button functions. Refer to the Tech-
nical Notes section of this guide for details.
One or Two Ethernet Connections
One 1000BASE-T Gigabit Ethernet (GigE)
connection is required for Model 348 operation.
If available and connected to the Primary-PoE
RJ45 jack, this connection can provide both
the Ethernet data interface and power for the
Model 348’s circuitry. A 100BASE-TX (100
Mb/s) connection may be adequate but not
optimal. A 10BASE-T (10 Mb/s) connection is
not sufficient.
A second 1000BASE-T Gigabit Ethernet
(GigE) connection can be made if Redundant
Dante is desired. The Model 348’s network

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MODEL 348
INTERCOM STATION
configuration must be set for Redundant for
this functionality to be active. PoE is not sup-
ported on the Secondary Ethernet connection.
The Secondary Ethernet interface can also
be used as a “loop through” connection such
as would be provided by an Ethernet switch.
This requires that the Model 348’s network
configuration be set for Switched. Using the
secondary port in this mode for applications
other than troubleshooting is not recommend-
ed. It will function reliably but “daisy chaining”
Ethernet signals can limit flexibility and pres-
ent a failure point.
The Ethernet connections are made by way
of two Neutrik etherCON protected RJ45
jacks that are located on the back of the Mod-
el 348’s enclosure. These allow connection
by way of cable-mounted etherCON connec-
tors or standard RJ45 plugs. The Model 348’s
Ethernet interfaces support auto MDI/MDI-X
so that crossover cables are not required.
The Model 348’s Primary Ethernet connec-
tion enumerates itself as a class 3 device. As
such, a PoE power-sourcing-equipment (PSE)
port could be required to supply 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 external 12 volts
DC source can be connected. For redundancy,
both PoE and the external source can be con-
nected 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 interruption 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 broad-
cast- or intercom-style communications head-
set. 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 elec-
trically 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 microphone
and headphone connections of a single- or
dual-ear intercom or broadcast-style headset.
The connector is labeled Headset A. Refer
to Figure 2 for connection details. The micro-
phone input connections are compatible with
most unbalanced dynamic or electret (low-
voltage DC-powered) microphones. A bal-
anced 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

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MODEL 348
INTERCOM STATION
for microphones that require P12 or P48 phan-
tom 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. Configuration choices us-
ing the STcontroller software application, as
discussed later in this guide, can be used to
create the desired monaural output. It’s impor-
tant not to connect together (short) pins 4 and
5 of the headset’s connector 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, pro-
vided in STcontroller, can be used to create
a monaural output.
It’s possible that some Beyerdynamic headset
interconnecting cable assemblies will termi-
nate its 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 ear-
piece 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 connected
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 3-conductor 1/4-inch or
3.5 mm TRS jack for the headphones. 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 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 configuration
standard which has the headphone left chan-
nel 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 personal computer or
gaming headsets. The microphones used in
these headsets are electret type which require
a low-voltage DC source for operation. The
Model 348 is able to provide this power and
requires only that the appropriate setting in the
STcontroller software application be selected.
Refer to Figure 3 for a detailed description of
the compatible TRRS plug.
Gooseneck Microphone
A threaded combination bushing/3-conductor
1/4-inch jack is incorporated into the top panel
of the Model 348. This allows direct connection
Figure 2. Headset A connection pinout chart

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MODEL 348
INTERCOM STATION
of the Studio Technologies’ GME-3-12 Goose-
neck Microphone. This unidirectional, elec-
tret microphone was designed specifically to
maximize performance in intercom and relat-
ed applications. The RTS/Telex/Bosch MCP-
90-series is also directly compatible and will
perform well. The two main requirements for
the gooseneck microphone are that it contain
an electret microphone and the interconnec-
tion be in the form of a 1/4-inch 3-conductor
plug with integrated threads that have a pitch
7/16-20 UNF.
The 3-conductor 1/4-inch jack associated with
the Model 348’s gooseneck bushing has a tip
connection 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 connections
are connected together as well as being “tied”
(connected) to the chassis.
The Model 348’s gooseneck bushing includes
a hex head socket set screw with a thread
pitch of 4-40 UNC. 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.
Dante Configuration
For audio to correctly pass to and from the
Model 348 requires, as a minimum, that sev-
eral Dante-related parameters be configured.
These configuration settings will be stored in
non-volatile memory within the Model 348’s
circuitry. Configuration will typically be done
with the Dante Controller software applica-
tion which is available for download, free of
charge, at audinate.com. Versions of Dante
Controller are available to support both the
Windows and the macOS operating systems.
The Model 348 uses the Broadway integrated
circuit to implement the Dante functionality.
The Model 348 is compatible with the Dante
Domain Manager (DDM) software application.
Audio Routing
The Model 348’s 11 Dante transmitter (output)
channels must be assigned to the desired
Dante receiver (input) channels on associated
equipment. This will route the Model 348’s
eight talkback, two monitor, and one hot mic
output channels to the devices that will be
“listening” to them. Within Dante Controller a
“subscription” is the term used for routing a
transmitter flow (a group of up to four output
channels) to a receiver flow (a group of up to
four input channels).
The number of transmitter flows associated
with a Broadway integrated circuit and,
as such, the Model 348, is 16 so there’s a
minimal chance of a flow limitation. These
flows can either be unicast, multicast, or
a combination of the two. (Note that in the
AES67 mode the Dante transmitter (output)
channels will function in multicast; unicast is
not supported.)
Using Dante Controller the desired audio
sources need to be routed to the Model 348’s
16 Dante receiver (input) channels. The exact
number utilized will depend on the specific
application. The first eight Dante receiver
Figure 3. Headset B (TRRS) connection pinout chart

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INTERCOM STATION
(input) channels are automatically assigned
to the rotary encoders and can be used for
listening to the associated intercom channels
or as general-purpose audio channel monitor-
ing. The second set of eight Dante receiver
(input) channels are associated with the IFB
(talent cue) functions. They will be utilized
only with channels that have their IFB function
enabled. The last Dante receiver (input) chan-
nel, labeled Aux In, can be used as both an IFB
program source and a mic input.
Unit and Channel Names
The Model 348 has a default Dante device
name of ST-M348- along with a unique suf-
fix. The suffix identifies the specific Model 348
that is being configured. The suffix’s actual
alpha and/or numeric characters relate to the
MAC address of the unit’s Broadway integrated
circuit. The 16 Dante receiver (input) audio
channels have default names of Ch 1 – Ch 8,
IFB Pgm 1 – IFB Pgm 7, and Aux In. The 11
Dante transmitter (output) audio channels have
default names of Ch 1 – Ch 8, Mon A, Mon B,
and Hot Mic. Using Dante Controller the
default device name and channel names
can be revised as appropriate for the specific
application.
Device Configuration
The Model 348 only supports an audio sample
rate of 48 kHz with no pull-up/pull-down values
available. Encoding choices are PCM 24,
PCM 16, and PCM 32 but in virtually all cases
the default selection of PCM 24 would be
appropriate. Clocking and Device Latency
can be adjusted if required but the default
values are typically correct.
Network Configuration – Dante Redundancy
The Model 348 allows connection of two Ether-
net signals. Two RJ45 jacks are located on the
unit’s back panel and are labeled Primary-PoE
and Secondary. In the network configuration
Dante Redundancy section of Dante Controller
how these ports function can be selected. The
choices are Switched or Redundant.
If Switched is selected (the factory default)
then the Model 348 will be able to establish
one connection with an Ethernet network. It
doesn’t matter which RJ45 jack is utilized,
although for PoE powering the jack labeled
Primary-PoE must be utilized. The other RJ45
jack can be used to interconnect with another
piece of networked equipment. If the Model
348’s network configuration is Switched ensure
that only one of the RJ45 jacks on the back
panel is connected to the LAN associated with
the Dante devices. If both of the Model 348’s
RJ45 jacks are routed to ports on the same
LAN this will typically “crash” the network!
(Although some of the latest/most advanced
Ethernet switches will automatically detect and
prevent an issue from occurring.)
If Redundant is selected then Dante’s re-
dundant networking implementation will be
enabled. In this case, separate network con-
nections should be made to the Primary-PoE
and Secondary RJ45 jacks. A personal com-
puter that’s running STcontroller will typically
be associated with the network that is connect-
ed to the Primary-PoE RJ45 jack.
When the Model 348 has been configured for
the Switched network mode one Dante IP ad-
dress will be associated with the network con-
nection that is made to either the Primary-PoE
or the Secondary RJ45 jacks. If the network
configuration has been configured for Redun-
dant then separate IP addresses and related
network parameters will be assigned to the
Primary-PoE and Secondary Ethernet ports.
Network Configuration – Addresses
By default, the Model 348’s Dante IP address
and related network parameters will be deter-
mined automatically using the DHCP or, if
not available, link-local network protocols. If

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MODEL 348
INTERCOM STATION
desired Dante Controller allows the IP address
and related network parameters to be manually
set to a fixed (static) configuration. While this
is a more-involved process than simply letting
DHCP or link-local “do their thing,” if fixed ad-
dressing is necessary then this capability is
available. But in this case, it’s highly recom-
mended that every unit be physically marked,
e.g., directly using a permanent marker or “con-
sole tape,” with its specific static IP address.
If knowledge of a Model 348’s IP address has
been misplaced there is no reset button or other
method to easily restore the unit to a default IP
setting.
Note that if the Model 348’s network configura-
tion has been set for Redundant then the Pri-
mary and Secondary Dante IP addresses and
related parameters can be independently con-
figured. This allows both to be automatic, both
to be manually configured, or one to be auto-
matic and the other to be manually configured.
AES67 Configuration – AES67 Mode
The Model 348 can be configured for AES67
operation. This requires the AES67 Mode to
be set for Enabled. By default, AES67 mode
is set for Disabled.
Model 348 Clocking Source
While technically the Model 348 can serve as
a Leader clock for a Dante network (as can all
Dante-enabled devices) in virtually all cases
the unit will be configured to receive “sync”
from another device. As such, the check box
for Preferred Leader associated with the
Model 348 would not be enabled.
Model 348 Configuration
The STcontroller software application from
Studio Technologies 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 (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
348 units that are to be configured.
Immediately after starting STcontroller the ap-
plication 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
will cause the associated configuration menu
to appear. Review the current configuration
and make any changes that are desired.
Changes made using STcontroller will be im-
mediately 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 distinc-
tive pattern to indicate that a command from
STcontroller has been received.
General Menu Page
The following configuration selections are
available in the General menu selections tab:
Microphone Input – Source
Choices are Headset, Gooseneck, and Dante
Aux In.
The microphone associated with a connected
headset, the gooseneck microphone, or the
Dante Aux In channel can be selected as the

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Model 348’s microphone (talk) audio source.
STcontroller can be used to select the desired
microphone source, as can the pushbutton
switch located on the Model 348’s front panel.
All three sources are available for use in “real-
time.” This field provides two functions, dis-
playing the active microphone source as well
as allowing the selection of it.
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 connected headset
has an electret microphone which requires
a source of low-voltage DC for operation. In
virtually all cases gaming or computer head-
sets 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) mi-
crophone. 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 Head-
set A connector.
Note that the Model 348 cannot supply P12 or
P48 phantom power that may be required by
balanced condenser (capacitor) microphones.
This should not pose an issue as phantom-
powered microphones are essentially never
associated with communications- or intercom-
style headsets that would be used for Model
348 applications.
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 ap-
plied no matter if the headset is connected
using the Headset A or the Headset B con-
nector. The compressor active LED, located
below the Headset A connector, can act as a
guide when setting the microphone preampli-
fier gain. When the headset mic is selected
as the Model 348’s microphone source and
a voice signal at a normal level is present
on the connected headset’s microphone the
compressor active LED should light intermit-
tently. 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 com-
pressor active 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 indicated, 38 dB is typically
a good initial choice for a headset that uses
a dynamic microphone while 32 dB would be
appropriate for a headset 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 se-
lected as the Model 348’s microphone audio
source the gain of the microphone preampli-
fier will operate from among five configurable
choices. The compressor active LED, located
adjacent to the Headset A connector, can act
as a guide when setting the gooseneck pre-
amp gain. When a voice signal at a normal
level is presented to the gooseneck micro-
phone 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 active LED is lit

Model 348 User Guide Issue 5, May 2021
Studio Technologies, Inc. Page 15
MODEL 348
INTERCOM STATION
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.
Microphone Input – Dante Aux In Trim
Choices are –12 dB, –6 dB, 0 dB, 6 dB,
and 12 dB.
When the Dante Aux In receiver (input) chan-
nel is selected as the Model 348’s micro-
phone audio (talk) source its level can be
configured from among five choices. This al-
lows the level of the signal associated with the
Aux In Dante receiver (input) channel to be
matched to the needs of the button functions.
Two of the configurable settings allow the sig-
nal level to be reduced, one setting maintains
the input level as is, while the other two allow
an increase in the signal level. In most cases,
selecting 0 dB, neither subtracting nor adding
gain, will be appropriate. This setting was pro-
vided to support situations where the Aux In
channel has a nominal level of –20 dBFS. But
this may not always occur and the configura-
tion choice should be changed as required to
achieve optimal operation.
Microphone Input – Dante Aux In as Mic In
Source
Choices are Disabled and Enabled.
A configurable setting determines whether
or not the Dante Aux In receiver (input) chan-
nel can be used as a microphone source.
This configuration should only be selected for
Enabled if an external source of talk audio,
typically provided by a second Model 348
unit, is going to be implemented.However, in
most cases, it will not be utilized and select-
ing Disabled would make the user experience
most simple. In this case pressing the micro-
phone source select pushbutton switch on the
Model 348’s front panel will not allow the Aux
In channel to be selected.
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
function is active on any or all of the unit’s
eight channels. An applicable function is one
that uses the headset’s mic, the gooseneck
microphone, or the Aux In. These include
Talk, Talk with 18 kHz Tone, IFB, and Talk with
Quindar Tones. 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 head-
phone output channels were connected to
audio playback devices that presented audio
energy in the same physical vicinity as the
active microphone then acoustic feedback is
possible. To prevent this from happening se-
lecting a dim configuration of 6, 12, or 18 dB
might be desirable.

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Speaker – Source
Choices are Off, Monitor A, and Monitor B.
The Model 348 includes an internal loudspeak-
er of which an audio source can be selected
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 loud-
speaker from interfering with the operation of
the selected microphone. Interference 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 provides 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 Con-
troller 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 channels
will not be impacted by the Model 348’s moni-
tor 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 utilized 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 transmitter (output)
channels Monitor A and Monitor B will follow
the action of the Model 348’s monitor output
rotary encoder. This mode is applicable if the
device or devices utilizing the Dante monitor
outputs require that the level of the source sig-
nals 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 in-
telligibility and minimize the chance of acoustic
feedback when loudspeakers are associated
with either or both Dante monitor outputs Moni-
tor A or Monitor B. A dim setting of 0 dB means
that the signal level on the Dante monitor
outputs will remain unchanged. (The signal will
be attenuated by 0 dB which is no attenuation!)
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 set-
ting of a rotary encoder is changed the LEDs
eight buttons will momentarily light. In most
cases it would be advantageous to enable this
function.

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MODEL 348
INTERCOM STATION
changes from gooseneck or Aux In to headset
the Dante monitor output channels (only when
configured for post-fader) and the speaker will
mute. And whenever the microphone source
selection changes from headset to gooseneck
or Aux In 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 avail-
able which provides a hot mic (always active)
function. The source of the Hot Mic output
channel will be the selected microphone
source, either the headset microphone, the
gooseneck microphone, or the Aux In Dante
receiver (input) channel. This can be very
useful but must be enabled only when an
application explicitly requires that the hot mic
output be active.
Note that even if the hot mic output is not en-
abled (function configured for Off) the Dante
Hot Mic transmitter (output) channel will still
be present. It will always appear in the list of
available channels as shown in Dante Con-
troller. But no audio will be present on the
channel unless the output has been enabled
(function configured for On).
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 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 – 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 incorpo-
ration of RGB (red-green-blue) LEDs located
within each rotary 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 signal level is
at risk of degrading audio performance. Note
that even if the Signal Present Display func-
tion 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 function
have LED indicators associated with them. The
LED intensity configuration choice allows the
overall intensity of these 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 switching between the headset
microphone, the gooseneck microphone, and/
or the Aux in. When the function is enabled,
whenever the microphone source selection

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MODEL 348
INTERCOM STATION
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).
Remote Control Inputs – Overview
The Model 348 provides two contact closure
inputs that can be utilized in installer-imple-
mented applications. They are physically
located inside the Model 348’s enclosure on
the main printed circuit board and accessible
using a 3-pin male “header” connector. A tech-
nician will first install a connector in the Model
348’s back panel and then make connections
to the header. Refer to the Technical Notes
section of this guide for details.
System – Remote Control Input 1
Choices are Off, Talkback 1 Button, Talkback
2 Button, Talkback 3 Button, Talkback 4
Button, Talkback 5 Button, Talkback 6 Button,
Talkback 7 Button, and Talkback 8 Button.
The action is performed when Remote Control
Input 1 is enabled will follow the configura-
tion selected from among nine choices. When
Off is selected no action will be associated
with Remote Control Input 1. When Talkback
1 Button, for example, is selected activating
Remote Control Input 1 will provide the same
function as pressing the Talkback 1 button.
The precise action of this remote control input
function will be identical to how the associ-
ated talkback button is configured. Separate
configuration choices allow the action of the
talkback buttons to be selected.
System – Remote Control Input 2
Choices are Off, Talkback 1 Button, Talkback 2
Button, Talkback 3 Button, Talkback 4 Button,
Talkback 5 Button, Talkback 6 Button, Talk-
back 7 Button, and Talkback 8 Button
The configuration choices for Remote Control
Input 2 are the same as those provided for
Remote Control Input 1.
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 button’s
function will normally be inactive and the
LEDs associated with the button will not be lit.
Whenever a button is pressed the associated
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 simi-
lar to the way in which pushbutton switches
often function on user stations associated with
broadcast or production intercom systems. If
the button is pressed and held the associated
function will be active. It will stay active until
the button is released. If the button is momen-
tarily “tapped” the status of the function will
change, either from inactive-to-active or from
active-to-inactive. The button’s green LED will

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Studio Technologies, Inc. Page 19
MODEL 348
INTERCOM STATION
the function is not active audio from the corre-
sponding Dante receiver (input) IFB program
channel will be routed to the corresponding
Dante transmitter (output) channel. When the
function is active the microphone (interrupt)
audio will be combined (mixed or summed)
with the IFB program audio source. The IFB
program audio source will be attenuated, fully
muted, or not changed, following the IFB Pro-
gram Dim 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 Dante receiv-
er (input) IFB program channel will be contin-
ually routed to the channel’s associated Dante
transmitter (output) channel. 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 transmitter (output) channel. This func-
tion can be useful for triggering other func-
tions associated with devices such as the
Model 5422A Dante Intercom Audio Engine.
20 kHz Tone: In this mode a 20 kHz sine
wave tone will be sent out the associated
Dante transmitter (output) channel. This func-
tion can be useful for triggering other func-
tions associated with devices such as the
Model 5422A Dante Intercom Audio Engine.
Talk with Quindar Tones: In this mode en-
abling the talk function will cause a 2525 Hz
sine-wave tone to be added to the Dante
transmitter (output) channel for 250 mSec.
This is called the intro tone. Then the se-
lected microphone source will be connected.
Upon the talk function no longer being active
be lit whenever the function is active. Upon
Model 348 power up the button 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, Talk with Quindar Tones, and
Disabled.
Talk: In this mode whenever the function is
active microphone audio will be sent out the
associated Dante transmitter (output) chan-
nel. This mode will typically be used as part
of an intercom or stage announce (SA) imple-
mentation. The sidetone function will be active
whenever the talk function is active.
Talk with 18 kHz Tone: This mode is similar
to the Talk mode except that an 18 kHz sine
wave tone is added (mixed or 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 capability was specifically provided for
use with the tone-activated (“TOX”) IFB func-
tion in the Studio Technologies’ Model 5422A
Dante Intercom Audio Engine product or the
IFB (talent cue) function in the Models 232,
234, and 236 Announcer’s Consoles. The
sidetone 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.
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 currently
active.
IFB: In this mode the Model 348 channel will
be used to create a broadcast-type IFB (inter-
rupted foldback or talent cue) source. When

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MODEL 348
INTERCOM STATION
Left and Right: In this mode the input audio
will be sent to both the left and right head-
phone output channels.
Monitor Routing
Choices are Off, Monitor A, Monitor B, and
Monitor A and B.
The Dante receiver (input) audio associated
with a Model 348 channel can be monitored
using the Dante monitor output channels. The
destination channel(s) can be configured 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 audio
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 input channel. The visual indication
is provided by the LED indicators associated
with each rotary encoder. The audible indica-
tion is provided by way of the Model 348’s
internal loudspeaker and, if configured appro-
priately, Dante monitor outputs.
Off: In this mode no visual or audible indication
in response to a call signal will be generated.
Visual Only: In this mode when a call signal
is detected in an input channel the LED in the
associated rotary encoder will flash orange.
Visual and Audible: In this mode when a call
signal is detected the LEDs in the associated
a sine-wave tone of 2475 Hz will be sent out
the Dante transmitter (output) channel for 250
mSec. (This is called the outro tone.)
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 attenua-
tion that will be applied to the Dante receiver
(input) source that is being used for program
audio when the IFB function is active for this
channel. (The program audio sources are IFB
Pgm 1-7 and Aux In.) 0 dB will configure the
channel to have no change in program au-
dio level. The talk audio will simply be added
(mixed or summed) with the program audio.
When Full Mute is selected the IFB program
audio source level will fully attenuate 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 receiver (input) 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 out-
put 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.