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INSTALLATION AND OPERATION INSTRUCTIONS 

 

INTRODUCTION 

Thank you for purchasing your American Fibertek MRM-1485 multimode mini video 
receiver with RS485 transceiver. Please take a few minutes to read these installation 
instructions in order to obtain the maximum performance from this product. 
 

FUNCTIONAL DESCRIPTION 

The MRM-1485 operates as half of a transmitter / receiver pair for the transmission of 
baseband NTSC, PAL, RS170, or RS343 video signals and bi-directional RS485 data. It 
is designed to operate with the MTM-1485 or RTM-1485 video transmitter with RS485 
transceiver over a single multimode fiber optic cable. 
 
The MRM-1485 converts a FM modulated optical fiber input into a single video output 
and a single RS485 output using a 1300 nm wavelength detector. The MRM-1485 also 
converts an electrical RS485 input signal into an optical RS485 output returning on the 
same fiber using an 850 nm wavelength source. This unit may be configured for two wire 
half duplex or four wire full duplex electrical interfaces. The M1485 Series product is 
designed to operate over an optical loss budget range of 0 to 12 dB. The MRM-1485 
operates on 50 um or 62.5 um multimode fiber. Refer to the data sheets for detailed 
performance specifications. 
 
This unit is contained in a compact and rugged aluminum housing with internal dc 
voltage regulation. The detachable terminal block and LED indicators provide for easy 
installation and monitoring of video, data, and dc power.  
 
The MRM-1485 is designed for mounting as a modular stand alone unit. For a rack 
mounted version please see the RRM-1485. 

 
INSTALLATION 

THE INSTALLATION OF THIS UNIT SHOULD BE MADE BY A QUALIFIED SERVICE 
PERSON(S) AND MUST CONFORM TO ALL LOCAL CODES. 
  
Mount the unit to a secure surface using #8 (3mm) hardware in four places. Mounting 
dimensions can be found on the connection diagram included with this manual. Be sure 
to allow sufficient room for the required minimum bend radius of the fiber cable used. 
 

 

POWER SOURCE 

This unit requires a +12VDC power source for proper operation. The DC input is diode 
protected. In the USA and in Canada an American Fibertek PS-12 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. 

 
POWER CONNECTION 

Power is supplied to the unit via a two pin terminal connector. Follow label on unit and 
customer connection drawing for proper orientation of +12 volt dc and ground. 

INPUT / OUTPUT CONNECTIONS 

The fiber optic connection is made via a ST connector located on the right side of the 
unit.  
 

Summary of Contents for MRM-1485

Page 1: ... Copyright 2003 American Fibertek Inc 0731JD Instruction Manual MRM 1485 Video Receiver With Bi directional RS485 ...

Page 2: ...on 3 Installation 3 Power Source 3 Power Connection 3 Input Output Connections 4 Data Configuration 4 Switch Jumper Settings 5 MRM 1485 Status LED Indicators 6 RS 485 Termination and Offset Bias Requirements 7 Warranty 8 Service Information 8 ...

Page 3: ...er to the data sheets for detailed performance specifications This unit is contained in a compact and rugged aluminum housing with internal dc voltage regulation The detachable terminal block and LED indicators provide for easy installation and monitoring of video data and dc power The MRM 1485 is designed for mounting as a modular stand alone unit For a rack mounted version please see the RRM 148...

Page 4: ... from the factory in the RS485 4 wire configuration In order to configure the unit for RS485 two wire operation the unit needs to be opened up and several switch settings and jumper pins need to be modified using the internal switch jumper settings shown on the next page The MRM 1485 is shipped from the factory with internal data input and output 120 ohm terminations switched on In order to remove...

Page 5: ...5 ...

Page 6: ...e RS485 input data from the electrical interface through the MRM 1485 and out onto the fiber The intensity of this indicator will vary with input data patterns however in typical applications it will cycle on and off as data is transmitted RS485 status associated with this LED is summarized below DATA TX LED RS485 Status Red Data Flow Present Off Data Flow Not Detected DATA RX A red LED indicator ...

Page 7: ...s at the furthest electrical devices at the ends of the wire pair For instance if several RS485 devices are connected in a daisy chain fashion the wire connection would loop across all devices in a chain The furthest two points in the chain would need to be terminated A termination resistor for RS485 input data can be selected in the MRM 1485 using switch 1 A termination resistor for RS485 output ...

Page 8: ...R THE FOREGOING WARRANTY THERE IS NO WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE OR OTHERWISE EXPRESSED OR IMPLIED WHICH EXTENDS BEYOND THE WARRANTY SET FORTH IN THIS AGREEMENT In any event American Fibertek will not be responsible or liable for contingent consequential or incidental damages No agreement or understanding expressed or implied except as set forth in this warranty...

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