Dual Channel C37.94-to-T1 Fiber Service Unit

  • Dual Channel C37.94-to-T1 Fiber Service Unit
Dual Channel C37.94-to-T1 Fiber Service Unit

Product Description

Dual Channel C37.94-to-T1 Fiber Service Unit

The new C37.94-to-T1 FSU is designed to convert any application devices with standard IEEE C37.94 compliant Short-Haul Fiber signals to an electrical T1 signal. The FSU allows for the conversion of up to two C37.94 output devices. The C37.94 fiber interface comes also with a non-standard Single-mode LED as an option for longer distances. The FSU is manufactured for wall/panel mounting, however, a rack mounting option will be available with 1RU (1.75”) 19” rack mount chassis.

The C37.94-to-T1 FSU is the perfect cost-effective solution to transport protective relaying devices or any industrial application devices reliably over an existing communications network, DS-1 Line or Leased T1 service.

C37.94 SHF Data Channels Over T1

  • Provides two independent IEEE C37.94 SHF Data Channels over industry standard DS1 signal

Easy Connection to Existing Network

  • Connect your protective relaying devices to a SONET or Multi-Service platform or Leased T1 line without the need for expensive channel banks or access gateway device

Cost-Effective Solution

  • Low cost solution to interface C37.94 compliant protective relaying equipment to existing communications network via T1 interface


  • Available in either Multi-mode or Single-mode fiber interface for either short or long distances

Rugged Design

  • Designed for harsh environments such as substations or exterior equipment buildings for wall mounting or with optional 1RU 19” rack mount chassis

User-Friendly Configuration

  • No software needed to configure the unit making it easy to configure through front panel switches
Dual Channel C37.94-to-T1 Fiber Service Unit Application Diagram


Front Panel
T1 Electrical:

  • One port per FSU
  • ANSI T1.403
  • ESF/SF and AMI/B8Z
  • 100 ohm twisted pair
  • RJ-48 Connector jack

C37.94 Optical

  • Two port pairs per FSU
  • IEEE C37.94 for N 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

T1 and C37.94 port loopback

Front Panel

  • 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)
  • Power Consumption: Less than 10W

Alarm Output

  • Alarm Relay Contact: Form C (SPDT)
  • Contact Rating: 100mA, @ 300Vdc, Non- inductive


  • Unit configured by DIP-switches, accessible through the front panel

Environmental and Regulatory Compliance


  • Operating Temperature: -20 C to +55 C
  • Operating Humidity: 95% RH Non-Condensing @ 40C
  • EN 60950:2002: Safety of IT equipment
  • EN 60825-2:2004, part 2: Safety of laser products


  • IEC 61850-3: Environmental
  • EN 61000-4-3 / -6-4: Radiated RFI Immunity
  • EN 61000-4-6 / -6-2: Conducted RFI Immunity
  • IEEE 1613: Environmental, ESD, shock & vibration

Power Supply and Alarm

  • EN 61000-4-4 / IEEE 1613: EFT 4kV
  • EN 61000-4-5: Surge
  • EN 60255-1 / IEEE 1613: 2.8kV Hi-Pot, 5kV impulse
  • EN 60255-22-1: Damped oscillatory
  • IEEE 1613 / ANSI C37.90.1: Oscillatory
  • IEC 60834-1: Power supply disturbance
  • Bellcore TR332 Issue 5, Method 1: MTBF >1,000,000 Hours, Case 3, Temp = 25 C

Mechanical Configuration

Self-Contained Wall Mount

  • Width: 5.13 inches (13 cm)
  • Height: 1.77 inches (4.5 cm)
  • Depth: 11 inches (28 cm)

1-RU Shelf

  • 1-Rack-Unit shelf, suitable for a standard 19” rack mount

Wall-Mount Ordering Catalog No.

  • RF-SP107560-1 T1 C37.94 SHF FSU 850NM LED MM
  • RF-SP107560-2 T1 C37.94 SHF FSU 1300NM LED SM

Rack-Mount Ordering Catalog No.

  • RF-SP107580-1 T1 C37.94 SHF single FSU 850NM LED MM
  • RF-SP107580-2 T1 C37.94 SHF single FSU 1300NM LED SM
  • RF-SP107580-3 T1 C37.94 SHF dual FSU 850NM LED MM
  • RF-SP107580-4 T1 C37.94 SHF dual FSU 1300NM LED SM

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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