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Low-Voltage DC Power Supply

Use the SEL-9321 Low-Voltage DC power supply as an inexpensive, robust means to convert high-voltage dc battery sources for use with communications or instrumentation devices.

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Transceiver Power Supply—Provide power to fiber-optic transceivers, like the SEL-2814 Fiber-Optic Transceivers With Hardware Flow Control, SEL-2812 Fiber-Optic Transceivers With IRIG-B, and SEL-3405 High-Accuracy IRIG-B Fiber-Optic Transceiver, as well as to the SEL-2886 EIA-232 to EIA-485 Interface Converter, when connected to devices that cannot provide power through their serial ports.

Communications Device Power Supply—Provide +5 Vdc and ±10 Vdc power to other communications or instrumentation devices. SEL provides cables that are 1.82 meters (6 feet) long with 2.5 mm or 0.7 mm power plugs.


    1. 1


    2. 2

      +/Hot Power Input

    3. 3

      –/Neutral Power Input

    4. 4

      –10 Vdc Output

    5. 5

      +10 Vdc Output

    6. 6

      Output Common

    7. 7

      +5 Vdc Output



  • Provide +5 Vdc and ±10 Vdc power for communications devices and accessories, from a station battery or ac source.
  • Reliable, robust, and backed by the SEL worldwide, ten-year product warranty. Meets IEEE and IEC standards for surge withstand, fast transient, and RFI immunity requirements in electric power substations.
  • Choose from three voltage inputs:
    • 24 Vdc
    • 125/250 Vdc or Vac
    • 48/125 Vdc or 125 Vac
  • Easily mount to any flat surface or DIN rail with the included mounting hardware.
  • 1.82 meter (6 feet) cable with 2.5 mm plug, compatible with SEL-2820, SEL-2824, SEL-3010, SEL-3021, and SEL-3022.
  • 1.82 meter (6 feet) cable with 0.7 mm plug, compatible with SEL-2814, SEL-2886, SEL-4388, and SEL-4391.

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

Product Certifications