html{display:none} SEL-2506 Rack-Mount Remote I/O Module | Schweitzer Engineering Laboratories


Rack-Mount Remote I/O Module

The SEL-2506 Rack-Mount Remote I/O Module has eight digital inputs, eight digital outputs, and a fiber-optic communications port. Connect an SEL-2506 to a fiber-optic port or transceiver on a protective relay to add digital I/O. Or, wire the SEL-2506 I/O to relay I/O to add  SEL Mirrored Bits teleprotection.

Starting At


Request a Follow-Up



Request a Follow-Up

Protection and Monitoring—Add simple bus protection using contact inputs and outputs from existing relays. Provide secure pilot communications for existing two- and three-terminal line applications. Add local or remote trip- and close-coil monitoring capability.

I/O Contact Expansion—Economically extend the number of I/O contacts on SEL relays that are Mirrored Bits communications-compatible.

Comprehensive Device Compatibility—Add Mirrored Bits communications to any protective relay (digital or electromechanical) or other intelligent electronic devices (IEDs) for advanced communications-based protection.

Enhanced System Reliability—Reduce or eliminate ground potential rise between IEDs by using fiber-optic links instead of conventional switchboard wiring.


    1. 1

      LEDs indicate the input and output status, channel activity, device status, and communications channel health

    2. 2

      Input and output LED labels are userconfigurable

    1. 1

      Connectorized screw terminals accept ring lugs with wires up to #10 AWG

    2. 2

      Level-sensitive contact inputs do not assert during dc grounds when applied to center-grounded systems

    3. 3

      Output contacts are rated for trip and close duty

    4. 4

      Standard serial or V-pin fiber port or optional ST® fiber port

    5. 5

      Alarm contacts signal self-test and communications channel statuses

    6. 6

      Wide-range power supply consumes less than 5 W



Protection and Monitoring
Add simple bus protection using contact inputs and outputs from existing relays. Add secure pilot communications to existing two- and three-terminal line applications. Add local or remote trip- and close-coil monitoring capability.

User-Configurable Labels
Allow clear indication of system function and status.

Expand the I/O of SEL relays that are Mirrored Bits-compatible.

Flexible Fiber-Optic Communications
Built-in bidirectional fiber-optic port. Ordering options provide operating ranges from 500 meters to 110 kilometers and compatibility with a variety of SEL fiber-optic transceivers and fiber types (see Table 1).

Replace control wiring to outside cabinets with fiber-optic cable to eliminate paths for dangerous voltages. All I/O terminals are behind the panel.

Use the communications monitoring feature to alarm when fiber-optic control cabling has been damaged, disturbed, or altered. Fiber-optic links are far less susceptible to electrical interference.

Easy Installation and Service
Install the rack-mount, compact two-rack-unit chassis. The SEL-2506 includes screw-terminal connector (STC) blocks for easy replacement of the unit.

Fiber-Optic Port Options:

Transceiver CompatibilityConnectorsFiberDistance (km)SEL Fiber-Optic Cable
SEL-2800 Fiber-Optic TransceiversV-SystemMultimode0 to 1/2SEL-C805
SEL-2815 Fiber-Optic Transceivers/ModemsSTMultimode2 to 15SEL-C807, SEL-C808
SEL-2829 Single-Mode Fiber-Optic Transceivers/ModemsSTSingle-mode0 to 23-
SEL-2830 Single-Mode Fiber-Optic Transceivers/ModemsSTSingle-mode16 to 80*SEL-C809
SEL-2831 Single-Mode Fiber-Optic Transceivers/ModemsSTSingle-mode16 to 110*-

*For distances below the minimum, use attenuators on the Transmit fiber.

Minimum Software Version

Latest Firmware Versions

There are no firmware versions available for this product.

Product Revision Firmware ID Date Available Serial Number
SEL-2506 R200 SEL-2505-R200-D20000919 9/19/00 ~2000263001
SEL-2506 R101 SEL-2506HS-R101-D20070412 4/12/07 ~2007102001
R101 is for SEL-2506 with high speed outputs. MOT string: 25060nn5nX

The Firmware IDs for older versions of the firmware can typically be found in Appendix A of the instruction manual.

Minimum Software Version

Instruction Manuals

Product Certifications