html{display:none} SEL-2505 Remote I/O Module | Schweitzer Engineering Laboratories


Remote I/O Module

The SEL-2505 Remote I/O Module has eight digital inputs, eight digital outputs, and a fiber-optic communications port. Use two optical fibers instead of 32 wires between outdoor or remote equipment and the control building to reduce costs, improve safety, and boost reliability. Or, connect an SEL-2505 to a fiber-optic port or transceiver on a protective relay to add digital I/O. Wire the SEL-2505 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.


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.

Expand the I/O of SEL relays that are Mirrored Bits compatible without modification to the control panel face. Make I/O status from any relay available to SEL Mirrored Bits schemes.

Replace control wiring to outside cabinets with fiber-optic cable to reduce dc ground exposure.

Use the communications monitoring feature to alarm when fiber-optic control cabling has been damaged, disturbed, or altered.

High Reliability and Rugged Design
Built to the same high standards as SEL protective relays, the SEL-2505 withstands vibration, electrical surges, fast transients, and extreme temperatures, meeting stringent industry standards. The printed circuit boards are conformal-coated to provide an additional barrier to airborne contaminants, such as hydrogen sulfide, chlorine, salt, and moisture.

Reduce project costs by using two fibers instead of 32 large-diameter wires, with less material expense, reduced trench and raceway requirements, and less labor for design, documentation, installation, testing, and maintenance.

The base model SEL-2505 is configured with an onboard V-pin fiber-optic transceiver/modem. To receive the unit with an onboard ST-type connection, this option must be selected when ordering.

Fiber-Optic Port Options:

Transceiver CompatibilityConnectorsFiberDistance(km)SEL Fiber-Optic Cable
SEL-2800V-SystemMulti-mode0 to 1/2SEL-C805
SEL-2815STMulti-mode2 to 15*SEL-C807, C808
SEL-2830STSingle-Mode16 to 80*SEL-C809
SEL-2812STMulti-mode0 to 4SEL-C807, C808

*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-2505 R200 SEL-2505-R200-D20000919 9/19/00 2000263001

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