Studio Technologies 5132 User Manual
Model 5132
Party-Line Interface
Module
User Guide
Issue 4, September 2012
This User Guide is applicable for serial numbers
M5132-00151 and later
Copyright © 2012 by Studio Technologies, Inc., all rights reserved
www.studio-tech.com
50179-0912, Issue 4
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Party-Line Interface
Model 5132
Module
Table of Contents
Introduction ................................................................... 5
Installation .................................................................... 8
Configuration ................................................................ 10
Operation ...................................................................... 10
Technical Notes ............................................................ 13
Specifications ............................................................... 17
Appendix A—Model 5132 Front Panel and
Printed Circuit Board (PCB) Dimensions ...................... 18
Appendix B–Interconnection Details ............................. 19
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Party-Line Interface
Model 5132
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Issue 4, September 2012 Model 5132 User Guide
Page 4 Studio Technologies, Inc.
Party-Line Interface
Model 5132
Introduction
The Model 5132 Party-Line Interface Module is a compact, self-contained unit for
use in custom broadcast, live-performance,
and general party-line intercom applications. The module provides a high-quality
2-channel party-line to analog line-level
(“4-wire”) audio signal interface in an easy
to use yet technically sophisticated package. The module’s basic functions include
two channels of 2-wire-to-4-wire conversion
with auto-null capability, input and output
level metering, a +28 volt DC party-line
power source with two channels of 200 ohm
intercom audio termination, and DC output control and status monitoring. With the
internal party-line power source enabled,
beltpack user devices can be directly connected. Alternately, the Model 5132 can be
connected into an existing party-line system
that includes a power source and intercom
audio terminations. Two analog inputs and
two analog outputs interface the Model
5132 with a variety of external audio transport, matrix intercom, and infrastructure
equipment. Module operation requires only
an externally-provided source of 12 volts
DC. Advanced features include remote control and monitoring capability when installed
with remote access modules available from
Studio Technologies.
Module
Applications for the Model 5132 include
sports broadcasting booth packages,
remote news gathering “fly packs,” stadium
audio/video interface (I/O) locations, and
government/corporate/performance space/
aerospace test infrastructure projects. The
number of Model 5132 modules used in a
project can vary widely—from one to dozens. And in each case the performance will
be completely “pro” with audio quality, reliability, and installation flexibility matching
that of larger-scale products. Typical ap
plications will find the Model 5132’s 4-wire
audio inputs and outputs being interfaced
with fiber-optical transport modules, matrix
intercom systems, and audio/video routers.
The flexibility of the Model 5132’s partyline intercom interface allows direct connection to either intercom beltpack devices
or an existing party-line intercom system.
The Model 5132 provides a full-featured
2-channel interface which includes two
2-wire-to-4-wire hybrid circuits with automatic nulling capability. The analog hybrid
circuitry provides excellent audio quality
and high return-loss. Audio level meters
provide confirmation of system performance during setup and operation. The
Model 5132’s party-line interface is acces
sible using a 3-pin male XLR connector.
This allows industry-standard party-line
Figure 1. Model 5132S Party-Line Interface Module Front and Back Views
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Party-Line Interface
Model 5132
Module
intercom user beltpacks to be directly
interfaced. With a maximum output current
of 180 milliamperes, up to three of the
popular RTS® BP325 devices can be
directly connected. Devices from ClearCom® are also compatible.
For applications with an existing party-line
intercom system the Model 5132 is also
directly compatible. The internal power
source and 200 ohm terminations can be
disabled by selecting the appropriate operating mode by way of a pushbutton switch
on the Model 5132’s front panel.
The 4-wire audio inputs and outputs were
carefully designed for use in permanent
as well as field applications. Filtering on
the inputs minimizes the chance that radio
frequency (RF) energy will interfere with
the audio input sources. Other components
were included to address ESD (“static”)
and DC over-voltage conditions. In addition, the DC power input is protected from
accidental polarity reversal.
For operation, the Model 5132 only requires connection of analog audio inputs
and outputs, along with an external source
of nominal 12 volts DC. The acceptable
input voltage range is 10 to 18, allowing
a variety of power sources to be utilized.
Power supply circuitry within the Model
5132 creates the voltages required for the
analog and digital circuitry.
Standard connectors are used throughout
the Model 5132. The party-line intercom
interface is accessed using a 3-pin male
XLR connector. The 4-wire audio input
and output connections are made using
5-position, 0.1-inch “header” connectors.
The DC power input and data bus connections use a 4-position, 0.1-inch header.
Low-cost IDC (insulation displacement)
mating connectors allow simple intercon
nection with the audio input, audio output,
DC input, and RS-485 data signals.
For compliance with international broadcast audio level standards two versions of
the Model 5132 are available. The Model
5132S supports SMPTE® audio levels
where the analog audio reference level
is +4 dBu. The Model 5132E supports
applications that require European
Broadcast Union (EBU) compliance with
an analog audio reference level of 0 dBu.
Model 5132 Party-Line Interface Modules
do not include a mounting enclosure or
chassis. They are intended for mounting
in custom 19-inch rack panels, equipment
boxes, broadcast furniture, “NEMA” I/O
boxes, or other specialized enclosures. It
is expected that integration firms will create
applications that use Model 5132 modules
as part of complete broadcast, production, corporate, and government solutions.
Sophisticated users will be able to create
“one-off” solutions to solve unique
challenges.
Party-Line Interface
The Model 5132’s party-line interface is
very flexible, offering excellent performance
when operating both “stand alone” or interconnected with an existing intercom system. When enabled, the internal party-line
intercom power supply circuitry provides
a low-noise, current-limited source with a
nominal 28 volt DC output. Termination networks provide the required 200 ohm impedance for the audio signals associated with
the two party-line intercom channels. With
these features the Model 5132’s party-line
intercom interface is essentially identical to
that created by stand-alone intercom power
supplies or powered master stations.
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Party-Line Interface
Model 5132
Module
Two LEDs, located on the Model 5132’s
front panel, provide an indication of the
power source’s on/off state and the state
of the DC voltage present on pin 2 of the
party-line intercom XLR connector. Logic
circuitry contained within the Model 5132
monitors the voltage on pin 2. When the
Model 5132 is providing intercom power
this function will monitor pin 2 for a lowvoltage/over-current condition. If detected,
the DC output will automatically enter a
protection mode. Once the fault condition
is removed normal operation will again
resume. When an external source of intercom power is present the pin 2 status LED
offers the user a simple “go/no go” indication for rapid troubleshooting.
An automatic 4-wire mute function is active whenever the Model 5132’s operating
mode has been set to support an external
party-line intercom circuit. (In this case
an external source of DC voltage and 200
ohm terminations is necessary for correct
operation.) The auto 4-wire mute function
helps to ensure that the Model 5132’s audio
interface circuitry will remain stable in “realworld” situations. This unique feature makes
certain that if a valid party-line intercom
circuit is not detected objectionable audio
content, such as oscillations and “squeals,”
will not be sent to the associated 4-wire
equipment.
Analog Hybrids with Auto
Nulling
The 2-wire-to-4-wire hybrids provide low
noise, low distortion, good frequency response, and high return-loss (“nulling”),
even when presented with a wide range
of party-line conditions. Unlike telephoneline (“POTS”) oriented DSP-based hybrid
circuits, the Model 5132’s analog circuitry
maintains extended frequency response.
With this wide audio bandwidth, naturalsounding voice signals can be sent to, and
received from, the connected party-line
user devices. This bandwidth also allows
high-frequency “call light” and “mic kill”
signals to pass through to connected 4-wire
equipment.
The Model 5132’s sophisticated auto nulling
function uses analog circuitry under microprocessor control to achieve significant
trans-hybrid loss. This return-loss “null” is
achieved by making a series of softwaredirected adjustments to account for the
resistive, inductive, and capacitive conditions that are present on the connected
party-line user devices and associated
cabling, as well as, if present, a connected
external intercom circuit. Whenever a user
presses the Model 5132’s auto null button
digital circuitry adjusts the 2-wire-to-4-wire
hybrids to achieve their maximum returnloss for both interface channels. The nulling
process is automatic, lasting less than
15 seconds, and only takes place upon
user request. The resulting null parameters
are stored in nonvolatile memory.
Audio Inputs and Outputs
Two analog line-level inputs and two outputs are associated with the 4-wire portion
of the Model 5132’s circuitry. These are
intended to interconnect with a variety of
devices, including matrix intercom systems,
audio-over-fiber transport systems, and
specialized audio equipment. The audio input and output circuitry is electronically balanced and capacitor coupled to minimize
the chance that hum, noise, or interfacing
issues will occur. The two Model 5132 ver
sions allow compatibility with equipment
that supports SMPTE (+4 dBu) and EBU
(0 dBu) analog audio level standards.
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