Fiber optic MM to SM Converter

Model: Article Number: 21-203

The 21-203 is a protocol independent optical-electrical-optical long haul converter link with data integrity control for high reliability.


The incoming multimode signal is sampled and packaged in 4B/5B code before transmission on the singlemode interface.

The incoming singlemode signal is decoded and error detected before reassembled and transmitted out the multimode interface. This conversion method offers a better (lower) error rate for low speed signals compared to transparent converters suitable only for high speed signals.

The 21-203 MM/SM converter is intended to extend optical reach for any low speed optical data signal into the long haul distances. Using a 21-203 the optical short reach signals can be sent without the need for additional and expensive communication systems normally found in long haul communications. When combined with the other products in Fibersystems tele protection communication product line this converter allows for a very cost effective solution. The 21-203 is particularly useful in differential line protection setups where dedicated fiber is available thus eliminating the need for multiplexers for the tele protection traffic.

The 21-203 is compatible with the standards based IEEE C37.94 optical interface for tele protection equipment and its protocol independence makes ideal for interoperation with any tele protection equipment suppliers products.

  • Standards compliant for power substation installation
  • Protocol independent up to 2Mbit/s MM 850nm (IEEE C37.94)
  • Power budget 30dB, 46dB up to 50dB in SM 1550nm
  • Single supply range from 48VDC to 250VDC or 110VAC to 230VAC
  • 19” mounting with only 200mm depth

Optical Interfaces

The optical interfaces uses standard SC connectors for multimode and LC connectors for singlemode fibers. The multimode interfaces uses 850nm light and the singlemode interface uses 1550nm.