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INSTALLATION AND OPERATION INSTRUCTIONS
INTRODUCTION
Thank you for purchasing your American Fibertek Series 746C singlemode four channel video
multiplexer with bi-directional multi-protocol data and contact closure. Please take a few minutes to
read these installation instructions in order to obtain the maximum performance from this product.
FUNCTIONAL DESCRIPTION
The MT-746C-SL operates as half of a transmitter / receiver pair for the digital transmission of four
simultaneous NTSC or PAL video signals along with one channel of field configurable bi-directional
data and one channel of bi-directional contact closure over one multimode fiber optic cable. The data
channel may be configured as RS485 data, RS422 data, RS232 data, or Manchester data. The RS485
channel may be configured for 2-wire (half duplex) or 4-wire (full duplex) with or without biasing. Switch
selectable internal 120 ohm terminations are available for RS422 or RS485 data.
NOTE: This unit is shipped with Data Channel 1 in the RS485 4-wire configuration. For other
configurations, please refer to the DATA CONFIGURATION section for changes to the default
switch settings. Data Channel 2 is set for contact closure and can not be reconfigured.
NOTE: This unit is shipped with data terminations off and data bias off for Data Channel 1. For
other configurations, please refer to the DATA TERMINATION / BIAS section for changes to the
default switch settings.
The MT-746C-SL multiplexes four video input signals along with one data signal and one contact
closure signal into a high speed serial data stream. This serial data stream modulates a laser at
1310nm wavelength. The MT-746C-SL also detects and demultiplexes a return optical serial data
stream containing one data signal and one contact closure signal at 1550nm wavelength.
This unit is contained in a rugged aluminum housing with internal dc voltage regulation. The detachable
terminal blocks and LED indicators provide for easy installation and monitoring of video, data, and
optical power.
The MT-746C-SL is designed for mounting as a modular stand alone unit. For a rack mounted version
please see the RT-746C-SL.
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.
Mount the unit to a secure surface using #8 (3mm) hardware in four places. See the drawing on the
next page for mounting dimensions. Be sure to allow sufficient room for the required minimum bend
radius of the fiber cable used.
POWER SOURCE
THIS PRODUCT SHALL BE POWERED BY A LISTED CLASS 2 POWER SUPPLY ONLY.
This unit requires a +12VDC power source with a current rating of 1.25 amps for proper operation. The
DC input is diode protected. In the USA and in Canada an American Fibertek PS-12D is supplied with
this unit. The negative side of the power input is directly connected to ground. ANSI/NFPA 70 Class 2
wiring is recommended.
