Studio Technologies 46A - Manual (Page 5)

Model 46A User Guide Issue 1, September 2014
Studio Technologies, Inc. Page 5
Introduction
The Model 46A is designed to interface
2-wire full-duplex party-line (PL) intercom
circuits with 4-wire audio circuits associ-
ated with matrix intercom systems. Other
specialized audio system interfacing appli-
cations can also be supported. The Model
46A provides two independent full-fea-
tured 2-channel interfaces. Each interface
contains two hybrid circuits which include
automatic nulling capability. The analog
circuitry, under software control, provides
excellent audio quality and high return-loss.
The interfaces are compatible with powered
and unpowered 2-wire party-line circuits.
They are capable of supplying DC power,
allowing direct operation of devices such as
user beltpacks. Configuration settings al-
low the 2-wire and 4-wire interface circuitry
to be compatible with a range of nominal
signal levels. Audio level meters provide
user confirmation of system performance
during setup and operation. Applications for
the Model 46A include television sports and
special event broadcasting, theme park and
theater installations, corporate events, and
industrial testing environments. Standard
audio connectors are used for all input and
output signals. The Model 46A mounts in
Model 46A Back Panel
Model 46A Front Panel
one space of a standard 19-inch rack
enclosure and requires 100-240 volts,
50/60 Hz for operation.
2-Wire Interfaces
The Model 46A’s 2-wire interfaces are
optimized for direct connection with
2-channel party-line intercom circuits.
In addition, single-channel party-line
intercom circuits can also be connected.
Many broadcast applications use the
2-channel TW-Series from RTS®, includ-
ing their popular BP325 beltpack. Other
industry-standard single- and 2-channel
PL intercom systems, including those from
Clear-Com®, are also directly compatible.
To provide optimal signal matching and
interface performance the nominal level of
the Model 46A’s 2-wire interfaces can be
selected. Using DIP switches, accessible
on the front panel, the nominal levels can
be selected to be either –10 or –14 dBu,
settings that should allow compatibility
with virtually all party-line systems. For ex-
ample, for applications that use equipment
from RTS the –10 dBu setting is appropri-
ate. For other equipment, such as that
from Clear-Com, the –14 setting is correct.
The Model 46A’s 2-wire interfaces can
correctly function with powered (“wet”)
or unpowered (“dry”) intercom circuits.