Symmetric High Bitrate DSL (SHDSL) Fiber Service Unit

  • Symmetric High bitrate DSL Fiber Service Unit
Symmetric High bitrate DSL Fiber Service Unit

Product Description

Symmetric High Bitrate DSL Fiber Service Unit

The new SHDSL-FSU (Symmetric High bitrate DSL Fiber Service Unit) is standalone device that serves as a media converter between electrical ITU-T G991.2 SHDSL signals and optical IEEE C37.94 fiber protocol signals. It is designed to enable modern C37.94 equipped application devices to communicate over legacy copper pilot wire infrastructure. The C37.94 fiber interface also comes with a non-standard single-mode LED as an option for longer distances between the application device and the FSU.

The C37.94-to-SHDSL FSU is the perfect cost-effective solution in a single stand-alone platform to transport protective relaying devices or any industrial devices reliably over existing long copper lines. The FSU unit is capable of switching or distributing SHF/TDM payload between individual HDSL ports.

C37.94 SHF Data Channels Over SHDSL

  • Provides single IEEE C37.94 SHF Data Channel over up to four industry standard SHDSL signals.

Easy Connection to Existing Copper Lines

  • Connect your protective relaying devices over existing long copper lines without the need for expensive communications devices.


  • The SHDSL signals can be conveyed over a single twisted pair, or 2 or 4 pairs (M-pair working). Using multiple pairs as oppose to single pair improve performance by increasing reach and payload bandwidth.

C37.94 Fiber Interfaces

  • Available in either multi-mode or single-mode fiber interface for either short or long distances.

Rugged Design

  • Designed for harsh environments.

User-Friendly Configuration

  • User-friendly configuration using pre-programmed profiles DIP-switches, or the Windows-based user interface.
C37.94/SHDSL FSU Application Diagram


C37.94 and SHDSL Connector Side

  • SHDSL: Up to 4-channels w/ M-pair bonding
    • ITU-T G.991.2 12/2003
    • DSL Terminal Unit Modes:
      STU-C (Central)
      STU-R (Remote)
    • Compression screw terminals connector
  • C37.94 optical: Single port pairs
    • IEEE C37.94 for N (1…12) times 64 kb/s.
    • Multi-Mode Version:
      50 or 62.5μm 820/850nm MM LED (2km)
      ST Connector
    • Single-Mode Version:
      9μm 1300nm SM LED (10km)
      ST Connector
      • Micro-USB:
        Unit Configurations

      Power and Alarm Connector Side

      • Power Supply: Compression terminal block
      • Chassis Ground: Grounding stud
      • Alarm Contacts: Compression terminal block

      Timing Modes

      • Internal
      • Through

      Power Supply Specifications

      • 48/125Vdc nominal (38 to 150Vdc)
      • 24Vdc nominal (19 to 32Vdc)
      • Power Consumption: Less than 20W

Alarm Output

  • Alarm Relay Contact: Form C (SPDT)
  • Contact Rating: 5A @ 30V dc/100mA @ 300Vdc, Non-inductive


  • Unit configured by DIP-switches for profile 1 & 2
  • Windows-based Graphic User Interface (GUI) via Micro-USB port

Environmental and Regulatory Compliance

  • Operating Temperature: -25 deg C to +55 deg C
  • IEC 60068-2-1/-2-2/-2-30: Environmental and Humidity
  • IEC 61000-4-6/-4-3: Conducted and Radiated RFI
  • IEC 60255-26: Conducted and Radiated Emissions
  • IEC 61000-4-8 / -6-2: Magnetic Field Immunity
  • IEC 61000-4-2: Electro Static Discharge (ESD)
  • IEC 61000-4-4: Electrical Fast Transients (EFT)
  • IEC 61000-4-5/-4-12: Surge Withstand and Damped Oscillatory
  • IEC 61000-4-5: Surge (4kV)
  • IEC 60255-5: Dielectric Strength and H.V. Impulse
  • IEC 61000-4-29: Voltage (Power) Interruptions
  • IEC 60255-21-1/-21-2/-21-3: Environmental -Shock, Vibration, Bump and Seismic
  • IEC 62368-1: Product Safety Compliance
  • CE Mark Compliance

Mechanical Configuration:

Self-Contained Mounting

  • Length: 297mm (11.7in)
  • Width: 170mm (6.7in)
  • Depth: 60.1mm (2.4in)

Available Files

Files Available in the Customer Area

Please visit Operating Manuals or Product/Software Downloads to download relevant files. Requires RFL Customer Account.

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Utility Industry Solutions

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Helping Utilities Move Forward in IP Migration

Multipoint-to-Multipoint Protective Relaying Signaling Using Digital Communications and Built-In Logic

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