html{display:none} SEL-2488 Satellite-Synchronized Network Clock | Schweitzer Engineering Laboratories


Satellite-Synchronized Network Clock

ENHANCEMENTS COMING SOON: 10 MHz outputs for synchronization of wireless communications like simulcast radio systems; holdover options with accuracy up to 1 µs after 24 hours; and PTP as an additional time source.

The SEL-2488 receives Global Navigation Satellite System (GNSS) time signals and distributes precise time via multiple output protocols, including IRIG-B and the Network Time Protocol (NTP). It provides Parallel Redundancy Protocol (PRP) support as a Dual-Attached Node (DAN) device for NTP time distribution. With an optional upgrade, the SEL-2488 can serve as a Precision Time Protocol (PTP) grandmaster clock, as defined by IEEE 1588-2008. The advanced capabilities of the SEL-2488 make it well-suited for demanding power utility applications—like synchrophasors, Sampled Values, and traveling-wave fault location—and for substations with multiple time synchronization requirements.

SEL-2488 Accessories

SEL-2407 and SEL-2488 Product Comparison Table

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Time Distribution—Configure the SEL-2488 clock’s eight BNC ports for demodulated IRIG-B, time pulse, or modulated IRIG-B (up to four ports). IRIG-B provides time output for protection applications, synchronizing relays, phasor measurement units, and other IEDs to within ±40 ns. Ethernet ports can distribute time using NTP to devices on the substation LAN, such as servers, computers, and other devices that set their time through NTP or the Simple Network Time Protocol (SNTP). With the PTP option, the SEL-2488 can act as a PTP grandmaster clock, supporting the default (Annex J), power system (IEEE C37.238-2011/2017), and power utility automation (IEC/IEEE 61850-9-3:2016) profiles. The SEL-2488 can serve NTP or PTP to four independent Ethernet networks. 

Network Resiliency—The SEL-2488 supports as many as two Doubly Attached Node implementing PRP (DANP) interfaces for separate PRP networks or two active-backup port bonded interfaces for Ethernet failover. When PRP is enabled, all network traffic through the PRP interface will be duplicated across the two redundant LANs that form the PRP network. The SEL-2488 implements PTP as a Doubly Attached Clock on ports where PRP is enabled. Active-backup port bonding logically combines two physical Ethernet ports into a single network interface with only one port active while the other serves as a failover backup.

Cable Delay Compensation—Provide time delay compensation for antenna cables and output cables on a per-port basis to preserve accuracy. The SEL-2488 clock’s cable delay compensation ensures high-accuracy time distribution in large facilities with dispersed IEDs or in installations where antennas must be mounted high on towers.

Event Notification—Log and forward event messages across an Ethernet network using standard syslog event messaging. The SEL-2488 can store up to 60,000 syslog messages locally and send messages to three remote syslog destinations. It can also provide event notification through Simple Network Management Protocol (SNMP) traps and the alarm contact.

Reliability—Choose a second, hot-swappable power supply to increase dependability. The SEL-2488 operates from –40° to +85°C (–40° to +185°F); is certified to IEEE 1613 Class 2, IEC 61850-3, and IEC 60255; and is backed by the SEL ten-year worldwide product warranty.

Authentication—Authenticate and authorize users with role-based user accounts and the Lightweight Directory Access Protocol (LDAP), increasing security and simplifying management efforts.

GNSS Vulnerability Mitigation—Maintain accurate time if GNSS time signals become unavailable as a result of solar flares, jamming, or an antenna failure. In the event of a signal loss, the SEL-2488 switches its time source to holdover with the standard TCXO holdover accuracy of 36 µs after 24 hours at constant temperature or with the optional OCXO holdover accuracy of 5 μs after 24 hours at constant or varied temperature. In the case of a GPS spoofing attack, in which a satellite system receiver locks to a counterfeit signal, the SEL-2488 and SEL-9524B GPS/GLONASS Precise-Time Antenna use signals from the GLONASS satellite constellation to validate GPS signals and identify the mismatches in timing information that this type of attack causes.

Easy and Secure Commissioning—Easily configure the SEL-2488 with an HTTPS web interface via the front Ethernet management port, which provides a graphical SkyView display for troubleshooting signal or antenna issues. The port is enabled by default and can be disabled if desired.

Time Synchronization for Wireless Communications—
Ensure reliable time synchronization in wireless communications, like simulcast radio systems used in 911 emergency response, using 10 MHz and 1 pulse per second (PPS) outputs.


    1. 1

      Status and activity LEDs

    2. 2

      Multi-information LCD screen

    3. 3

      Clock status LEDs

    4. 4

      Local management port

    1. 1

      Alarm and timer contact

    2. 2

      Eight configurable BNC time outputs (demodulated IRIG-B, pulse per second [PPS], kPPS, and modulated IRIG-B)

    3. 3

      Four standard Ethernet ports

    4. 4

      DB-9 port for IRIG-B output or pulse output

    5. 5

      Antenna connection (TNC)

    6. 6

      IRIG-B input (future)

    7. 7

      Standard power supply

    8. 8

      Optional redundant, hot-swappable power supply



Accurate—Synchronize with precise time accuracy to within ±40 ns to UTC for power protection applications. Cable delay compensation can be configured for antenna cables and output cables per port to preserve high accuracy. If a GNSS lock is temporarily lost, the standard TCXO holdover accuracy is 36 µs after 24 hours at constant temperature or the optional OCXO holdover accuracy is 5 μs after 24 hours at constant or varied temperature.

Powerful Time Distribution—Distribute time from eight time BNC outputs and one DB-9 output, which are configurable for IRIG-B or time pulse outputs. The DB-9 port can be used with SEL-2812 Fiber-Optic Transceivers With IRIG-B or SEL-3405 High-Accuracy IRIG-B Fiber-Optic Transceivers to send IRIG-B long distances over fiber-optic cable. The SEL-2488 also includes four standard Ethernet ports, which provide NTPv4. With the PTP option, the SEL-2488 can act as a PTP grandmaster clock, supporting the default (Annex J), power system (IEEE C37.238-2011/2017), and power utility automation (IEC/IEEE 61850-9-3:2016) profiles. The SEL-2488 can distribute NTP and PTP to four independent networks or two separate PRP or Ethernet failover networks. Ethernet ports are orderable in pairs and are available in copper as well as single- or multimode fiber.

Secure—Secure access to the SEL-2488 through X.509 certificates, user-based accounts, Lightweight Directory Access Protocol (LDAP) authentication, and complex passwords. The SEL-2488 supports syslog, a standard for event record logging that integrates with existing log management systems. With satellite signal verification, the SEL-2488, when installed with a dual-constellation antenna, uses signals from two satellite constellations to validate GNSS time signals, providing a layer of protection from spoofing attacks.

Reliable—Add power source redundancy with an optional second, hot-swappable power supply. The SEL-2488 operates in a broad temperature range of –40° to +85°C (–40° to +185°F) and meets IEEE 1613 Class 2, an electric transient and interference standard for communications products in electric utility substations.

Easy to Use—Commission and manage the SEL-2488 through a secure HTTPS web interface with SkyView and acSELerator QuickSet SEL-5030 Software. The front panel of the SEL-2488 includes an LCD multi-information display plus LEDs for status and an Ethernet management port, which supports DHCP Captive Portal for simplified access to the device web interface.

Mounting Options
The SEL-2488 is available in a panel-mount or rack-mount hardware package to suit your application needs.

SEL-9524 GNSS Antenna
The SEL-9524 is a ruggedized GNSS antenna manufactured in our Pullman, Washington, facility and is available as an ordering option or as an accessory. It includes a dual-constellation GPS/GLONASS option or a GPS-only option. The antenna operates using 3.5–6.0 V and includes an LED for diagnostic information. It has a strong gain of greater than 40 dB.

SEL recommends pairing the SEL-2407 and SEL-2404 with the SEL-9524A GPS GNSS Antenna. The SEL-9524B GPS/GLONASS GNSS Antenna is to be used with the SEL-2488. The legacy 235-0113 and 235-0103 Bullet Antennas are still available in limited quantities.



Minimum Software Version


Precise and Accurate SEL-2488

Latest Firmware Versions

There are no firmware versions available for this product.

Product Revision Firmware ID Date Available Serial Number
SEL-2488 R110-V0 SEL-2488-R110-V0-Z010001-D20240124 2/3/24 ~1240340001

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

Minimum Software Version

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