Studio Technologies 240 - Manual (Page 8)

Issue 1, August 2013 Model 240 User Guide
Page 8 Studio Technologies, Inc.
talk functions are active. This is specifically
provided as a “trigger” to mute loudspeaker
systems that are located in the same
physical area as the Model 240.
Signal Flow
This document can only highlight some of
the Model 240’s capabilities. For a detailed
view of the unit’s signal flow it’s recom-
mended that the block diagram, located
at the end of this guide, be reviewed.
Rugged, Flexible, Reliable
The Model 240 uses a rugged desktop
enclosure with a removable security plate
on the bottom that provides access to the
many configuration switches and trim pots.
(The unit does not have to be disassem-
bled to be configured!) Laser-engraved on
the plate is a complete set of configuration
information so that field setup can be fast
and accurate. Four openings in back of the
Model 240’s enclosure allow installation of
a variety of option modules. These allow a
range of additional features and resources
to be easily added for a myriad of poten-
tial applications. Numerous 3-pin header
connectors are provided on the Model
240’s printed circuit board assembly. These
provide access to all audio inputs and
outputs, along with many special input and
output signals. These include four contact
inputs associated with the four pushbutton
switches. A competent technician can use
them to create a highly-customized feature
set for meeting the exact needs of specific
applications.
The four pushbutton switches associated
with the talk functions use gold-plated con-
tacts for reliable long-term operation and
include backlighting using white LEDs. A
data link allows two Model 240 units to be
interconnected as an integrated 2-location
system. The status of the talk channels is
communicated via the data link; combining
of the main output audio signals is done
passively. The Model 240 can be powered
by an external source of 24 volts DC.
Alternately, a connected party-line inter-
com circuit can provide the required power.
Installation and
Setup
In this section interconnections will be
made using the input and output con-
nectors located on the Model 240’s back
panel. The main outputs, line inputs, and
party-line (PL) intercom signals are inter-
faced by way of 3-pin XLR connectors.
A headset is connected using a 5-pin XLR
connector. A 2.1 x 5.5 mm coaxial jack
allows connection of an external 24 volt
DC power source.
System Components
The following is included in the shipping
carton: Model 240 Producer’s Console,
Model 240 User Guide, button label sheet,
and 24 volt DC power supply.
Headset Connection
The Model 240 is compatible with head-
sets that have a dynamic microphone
and single- or dual-earpieces. These are
commonly referred to as single- or dual-
muff headsets. The microphone portion
of compatible broadcast-quality headsets
will typically have a source impedance of
200-300 ohms. The impedance of the ear-
pieces can range more widely. Connecting
devices with earpiece impedance of 100
ohms or greater is preferred. Some com-
mon devices have an earpiece impedance
of 50 ohms and while not optimal they
should also function correctly.