Transmit 8 Contact Closures Over a Single Fiber

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  • Available with ST or SC Connectors
  • Convenient LED status indicators
  • Single and Multimode fiber models available
  • RX side includes alarm contact for status monitoring
  • Alarm contact may be set to Normally Open or Normally Closed
  • DC power is not polarity sensitive, simplifying wiring duties
  • Environmentally rugged with wide operating range: -40˚F to +158˚F (-40˚C to +70˚C)
  • Single slot RLH Fiber Link Card form factor allows up to 12 cards in a 12 card housing, or multiple housings for larger installations
  • Limited Lifetime Warranty

  • Made in USA

The RLH 8 Channel Contact Closure fiber link card provides a transmission of up to eight independent contact closure signals over one optical fiber. The transmitter card provides the electrical-to-optical interface between dry contact closure relay input and a fiber strand.

The receiver card provides the optical-to-electrical interface between a fiber strand and normally-open relay contact output. Both cards are powered by a 24-56VDC source and the receiver card provides LED indicators to display relay conditions, power, and fiber carrier receive.

This fiber link card is designed to be installed into any of the RLH fiber link card housings, and occupies a single card slot.


For a comprehensive review of the product specs, please see the Data Sheet, or feel free to contact us with any questions.

Transmission Method:
Frequency modulated light via two optical fibers

Multimode: 850nm
Singlemode: 1310nm
SM Long Haul: 1310nm

Fiber Type/Distance:
Multimode (62.5/125µm): 6dB / 1.2 miles (2km)
Singlemode (9/125µm): 8dB / 9 miles (15km)
Singlemode Long Haul: 24dB* / 29 mi. (48 km), min. required loss -8dB

Note: Distances equated using industry standard fiber and connector attenuation of 3dB/Km. Fiber condition, splices and connectors may affect actual range.

Fiber Connector Type:
ST or SC

7in. x 4in. x 1in. (177.8mm x 101.6mm x 25.4mm)
(Standard RLH Fiber Link Card Form Factor)

Operating Temperature:
-40˚F to +158˚F (-40˚C to +70˚C)

Operating Humidity:
95% non-condensing


Download the RLH Data Sheet

Download the RLH User Guide

Download Layout

Download Layout

Download the DXF File

Download the DXF File

Download the DWG File

Download the DWG File

  • A complete system requires one TX unit and one RX unit

Please submit a quote request or contact your RLH sales representative for pricing and delivery information.