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© Copyright 2005, American Fibertek, Inc. 1207JD
Six Channel Video Multiplexer
Instruction Manual
with Bi-directional Data
MTX-8685C
MRX-8685C
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Table of Contents
Functional Description ........................................................................3
Installation...........................................................................................3
Power Source .....................................................................................4
Power Connection...............................................................................4
Input / Output Connections .................................................................4
Typical System Data Connections .....................................................5
Data Configuration Switches...............................................................6
MTX-8685C Status LED Indicators.....................................................8
MRX-8685C Status LED Indicators.....................................................9
Data Termination Requirements.......................................................10
Offset Bias - RS485 Data Signals.....................................................11
Warranty / Service Information .........................................................12
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INSTALLATION AND OPERATION INSTRUCTIONS
INTRODUCTION
Thank you for purchasing your American Fibertek Series 8685C multimode six channel video
multiplexer with bi-directional data. Please take a few minutes to read these installation
instructions in order to obtain the maximum performance from this product.
FUNCTIONAL DESCRIPTION
The 8685C Series units operate as a transmitter / receiver pair for the transmission of six
simultaneous, real time baseband NTSC/PAL video signals with field configurable bi-directional
data over a single multimode fiber optic cable.
This link can accommodate either a single RS485 interface (2 or 4 wire) or both an RS422 and
RS232 interface. When used in RS422/RS232 mode, each interface functions independent of
the other. These units are factory shipped configured in the RS485 (4 wire) configuration.
The MTX-8685C transmitter accepts six video inputs and multiplexes these signals along with
the data signals onto a single optical output port for connection to the fiber transmission system.
Correspondingly, the MRX-8685C receiver converts the optical signal to six independent video
output signals along with the data signals.
The 8685C Series units operate on 50 um or 62.5 um multimode fiber. Refer to the data sheets
for detailed performance specifications.
The individual units may be configured for rack mounting or wall mounting depending upon the
position of the included mounting hardware.
INSTALLATION
THIS INSTALLATION SHOULD BE MADE BY A QUALIFIED SERVICE PERSON AND
SHOULD CONFORM TO THE NATIONAL ELECTRICAL CODE, ANSI/NFPA 70 AND LOCAL
CODES.
To install the MTX-8685C or MRX-8685C it is first necessary to mount the rack flanges to the
unit.
For rack mounting the ears are installed on the
sides of the unit with the surfaces that have
oval holes flush with the front of the unit as in
Figure 1. Mount the ears with the #10 flathead
screws provided. To mount in the rack cabinet,
use mounting screws that are appropriate for
the rack cabinet being used.
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For mounting the unit flush to a wall or other rigid
surface, the ears may be installed on the sides with
the oval holes flush with the bottom of the unit as in
Figure 2. Mount the ears with the #10 flathead
screws provided. Mount the
unit to a rigid surface using #10 (5mm) screws.
POWER SOURCE
The internal power supply accepts universal line voltage. Any mains supply from 100 to 240
VAC, 50 to 60 Hz, may be used without modification or adjustment. A universal power
connector is provided on the rear of the unit to facilitate connection to the power mains.
POWER CONNECTION
The unit is supplied (in the US and UK only) with a three conductor power cord. The “ground”
conductor is directly connected to the chassis.
INPUT / OUTPUT CONNECTIONS
The fiber optic connection is made via a ST connector located at the back of the unit. Be sure to
allow sufficient room for the required minimum bend radius of the fiber cable used.
Video input and output connections are located on the rear of the unit. A BNC connector is
provided for each channel. The video inputs are connected to an appropriate 75Ω baseband
video source such as a camera or a video recorder output. The 75Ω video outputs can be
looped through typical baseband video inputs of switchers, recorders and other equipment as
required. For proper operation, the outputs must be terminated with 75Ω. For optimum
performance the video cables should be the shortest length of coax practical.
Data input and output connections are located on the rear panel terminal block. A mating plug
connector is provided. The figure below identifies the specific connections for the RS485 data
connections. See next page for RS422 / RS232 data connections.
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