Two-Way Signaling of a Contact Closure Over Fiber

Industrial Media Converters - Bi-Directional Contact Closure
DIN Mount

This Bi-Directional Contact Closure Fiber Link system provides two-way transmission of a contact closure signal over optical fiber. Applications include alarm event triggering, building automation, environmental control systems, fire & alarm systems, gate control, traffic signal control equipment, and more.

This contact closure system is designed to operate over an extreme temperature range, providing reliability in non-temperature controlled environments. Accepts a wide power input rage of 12 through 48 volts DC allowing for flexibility in installation.


  • Convenient LED status indicators
  • Available with ST connectors for single or multimode fiber
  • Input will sense a dry contact closure
  • Output relay is rated to support to 60 Watts
  • Can be powered by 12-48VDC
  • Pluggable terminal blocks
  • Alarm contact for status monitoring
  • Wide operating temp -40°F to +158°F (-40°C to +70°C)
  • Standard T35 DIN rail or wall mountable
  • Limited Lifetime Warranty
  • Made in USA

Multimode: 850nm
Singlemode: 1310nm

Fiber Type/Distance:
Multimode (62.5/125µm, 50/125µm): 1.2 miles (2km)
Singlemode (9/125µm): 9 miles (15km)
Singlemode Long Haul: 29 mi. (48 km)

*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:

Steel and Aluminum Alloy, Powder coated

Mounting Style:
Standard DIN rail (TS-35) or wall mount

H4.93” x W1.2” x D3.5” (100mm x 31mm x 89mm)
Not including connectors, Din Clip, or Wall Mount Ears


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

General Information
Bi-Directional Contact Closure System Application
Bi-Directional Contact Closure System Application
Fiber Cable Continuity Monitor
Fiber Cable Continuity Monitor


Lead Time: 1 to 2 Weeks*

For product questions, volume pricing and/or delivery outside of the US and Canada, please contact sales.


Bi-Directional Contact Closure

Product configurationModeDistanceConnectorFibersPart numberPrice
Multimode, ST, 2km/1.2 miles, Dual FiberMultimode2km/1.2 milesSTDual Fiber1CD-IO-03-1$310.00
Singlemode, ST, 15km/9 miles, Dual FiberSinglemode15km/9 milesSTDual Fiber1CD-IO-20-1$410.00
Singlemode, ST, 48km/29 miles, Dual FiberSinglemode48km/29 milesSTDual Fiber1CD-IO-21-1$510.00
  • A complete system requires two devices with the same part number

*Lead times are estimates and may vary. You will be contacted within 1 business day to go over the details of your order. If you require a specific date, let us know!
*Days = Business Days

WarningWarning: This product can expose you to chemicals including arsenic, which is known to the State of California to cause cancer. For more information, go to

RLH Industries - Fiber Optic Link
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