Black Box Fiber Drivers

Ensure Reliable Transmission Over Fiber

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What's special about these fiber optic drivers?

  • High-performance drivers enable you to send RS-232 data across interference-free optical links
  • Sends RS-232 data, at up to 76.8 kbps, from serial devices to a server over multimode fiber cable
  • Switch-selectable DTE/DCE option, set to perform like a DTE so it can communicate with another DCE device, no special cables are needed
  • Click for More Features

The Black Box high performance fiber drivers are powered to ensure continuous, reliable transmission over fiber. These fiber drivers enable you to send RS-232 data across interference-free optical links, transmit data at up to 76.8 kbps, and reach distances of 2.5 miles at any speed.

BB-MD940A-F Fiber Driver ST/25 Female 1" H x 2.7" W x 4.2" D 1.4 lbs
BB-MD940A-M Fiber Driver ST/25 Male 1" H x 2.7" W x 4.2" D 1.4 lbs

  • Reach distances of 2.5 miles (4 km) at any speed
  • Autosensing 110–220-VAC power supply ensures reliability and continuous transmission
  • Coupled power variations are compensated by a range select feature
  • Supports RS-232 async, bidirectional transmission
  • Use with multimode fiber cable
  • 1 Year Double Diamond Protection
Data Format Asynchronous, bidirectional
Data Rate Transparent up to 76.8 kbps
Distance Dependant on type of multimode cable, power budget, and loss/km; preset ranges
Fiber Cable 850 nm multimode
Flow Control X-ON / X-OFF
Operation Full-duplex
CE Approval Yes
Interface RS-232 (DCE or DTE switch selectable)
Connectors (2) ST®; (1) DB25 M or F
Power 5 VDC @ 600 mA
External: 110-220 VAC, 50-60 Hz, autosensing
Operating Temperature 32°F to 114°F (0°C to 45°C)
Size 1" H x 2.7" W x 4.2" D (2.5 x 6.9 x 10.7 cm)
Weight 1.4 lbs (0.6 kg)


The Double Diamond Warranty is our no-questions-asked warranty that protects your BLACK BOX® brand products from accidental damage, including drops, water, and power surges. Most products come with a one- or two-year warranty. Some products, such as copper cables, manual switches, cabinets, and racks, are guaranteed for life! During the warranty period, Black Box will repair or replace your damaged equipment within one week of receipt at NO CHARGE!





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by PowerReviews
Black Box Fiber Driver St/25 Female

(based on 1 review)

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Reviewed by 1 customer

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Black Box Media converter

By Sandman1452

from Cali

Verified Buyer


  • Pins configurable
  • Price right
  • Simple to use
  • Small


  • Din rail mounts

Best Uses

  • Need to make jumper setti
  • Tight small mounting

Comments about Black Box Fiber Driver St/25 Female:

I purchased this for a application to connect fiber into old equipment, this device will allow for pins configuration simply by changing toggle switch. We were able to install this product quickly and was able to document setup and configuration. The only negative about product is would be nice if you could mount on din rail or provide a mounting bracket.

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