VCL-TP, IEEE C37.94 Optical Teleprotection Repeater


VCL-TP, IEEE C37.94 Optical Teleprotection Repeater is an extremely reliable and flexible C37.94 transmission product that re-generates and re-times the C37.94 optical signals and removes any residual jitter and wander, thereby making it suitable for extending C37.94 signals over long optical fiber links.

The VCL-TP, C37.94 is available with 1+1 Optical Link Redundancy (C37.94), 1+1 Redundant Power Supply options.


  • May be used as a C37.94 Signal Converter - to convert an optical signal from IEEE C37.94 compliant 850nm Multi-Mode C37.94 Distance Protection Relay and transmit it up to a distance of 180 KM on Single Mode optical fiber.
  • Compatible with C37.94 Distance Protection Relays from all major manufacturers.
  • May be used as a C37.94 Optical Repeater to extend the reach of the VCL-TP, Teleprotection Equipment beyond the distance of 180 KM. The combined reach of the VCL-TP, Teleprotection Equipment with one mid-span VCL-TP, C37.94 Optical Repeater may be up to 360 KM.
  • Option of 1+1 Route / Path Protection for C37.94 Optical interface with less than 5ms link switching / link recovery time in the event of the working optical link failure.
  • IRIG-B Synchronization for time-stamped alarms.
  • Immunity to Voltage Dips, Short Power Supply Interruptions and Voltage Variations as per IEC 61000-4-11 specifications.

Transmission Interface options include

  • IEEE C37.94 compliant 850nm (50 /125 um and 62.5/125um) Multi-Mode optical fiber interface for connecting to C37.94 Distance Protection Relays.
  • IEEE C37.94 compliant 1310nm / 1550nm (9/125 um) Single-Mode optical fiber interface for transmission over long-reach, single-mode optical fiber links to extend Teleprotection Signals over long optical fiber links ( < 40 KM, < 80 KM, < 120 KM, < 150 KM and < 180 KM).
  • Option of 1+1 redundant optical path protection / route protection.
  • Laser: Class I (for Single-Mode Optical Interface) - Eye-safe as per EN 60825-1 specifications.


  • Less than signal 1ms transfer time over a 180 KM optical span.

Error Detection and Coding

  • Line Code Violation Detection
  • LOS Detection
  • Signal Re-timing, Re-generation and Block Command Encoding as per IEEE C37.94 for reliable transmission.

Standards and Compliances

  • Compliant with IEC 60834-1 and IEC 834-1 specifications and standards.
  • Event and Alarm Logging
  • Time-Stamped Alarm Logging
  • Built-In (RTC) Real Time Clock
  • IRIG-B Time Synchronization option to synchronize the RTC time-stamps with GPS.

Management Interface

  • RS232 serial, USB serial interfaces for local terminal access.
  • 10/100BaseT Ethernet Interface for remote access over an IP network.

Access and Monitoring

  • Command Line Interface (English text commands).
  • Telnet
  • SSH
  • SNMPv2 Traps.
  • Encrypted Password Protection
  • Maintains an access log of over 10,000 most recent entries for security audit.

Power Consumption

  • < 15 Watts.

Other Regulatory Compliances

  • Meets CE requirements
  • Complies with FCC Part 68 and EMC FCC Part 15.

Power Supply Options

  • 24V DC
  • 48V DC
  • 110V DC / 125VDC
  • 220V DC / 250V DC
  • 1+1 Redundant Power Supply.

EMI, EMC, Surge Withstand and other Compliances

EN 50081-2 EN 50082-2 IEC 60068-2-29
IEC 61000-4-6 (Conducted Immunity) IEC 60068-2-6 IEC 60068-2-2
IEC 60068-2-78 IEC 60068-2-1 IEC 60068-2-14
CISPR 22 / EN55022 Class B (Conducted Emission and Radiated Emission)
IS 9000 (Part II Sec. 1-4, Part III Sec. 1-5, Part IV, Part 14 Sec. 1-3)
IEC 60870-2-1 IEC 61000-4-5 IEC 61000-4-12
IEC 61000-4-3 (Radiated Immunity) IEC 61000-4-8 IEC 61000-4-16
IEC 61000-4-2 IEC 61000-4-10 Telcordia GR-1089 Surge and Power Contact
IEC 61000-4-4 IEC 61000-4-11 Telcordia GR-1089 Surge and Power Contact
  • ESD, Voltage and Surge Withstand: Meets and exceeds IEC 61000-4-2, IEC 61000-4-4, IEC 61000-4-5, Level 4 specifications.
  • Immunity to Voltage Dips, Short Power Supply Interruptions and Voltage Variations meets and exceeds IEC 61000-4-11, Level 1 specifications.


Application # 1: VCL-TP, C37.94 Optical Repeater

E1 Teleprotection Equipment

Application # 2: VCL-TP, C37.94 Optical Converter

Data Sheet

Data Sheet optical repeater