ISM

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Industrial, Scientific and Medical uses of RF. In other words, non-communication services. In the USA, ISM bands are regulated under Part 18 of the FCC rules.

In recent years, the ISM bands have become extremely popular for short-range communications systems, including things like WiFi, some cordless phones, Bluetooth and dozens of other services. Some of the ISM bands overlap with Part 15 bands. This can lead to significant confusion. Remember that Part 15 low power systems are designed and regulated as radio communications systems - "intentional radiators" as the FCC calls them. Devices operating on the ISM bands must accept any interference from ISM operations (as long as the ISM system is operating within the technical standards of the country the equipment is operating in.

Good examples of this include the Part 95 CB radio service, the Part 95 Remote Control Radio Service, the 26.960 MHz - 27.280 MHz Part 15 service and the 26.957 MHz - 27.283 MHz - 27.12 MHz center frequency - all operating in the same spectrum.

Other examples include the 2.4 GHz band, used by Wi-Fi, Bluetooth, analog and digital video and audio links, baby monitors, intercoms, cordless phones (although most cordless phones have moved to the DECT system, as well as ISM devices such as microwave ovens on 2.45 GHz / 2450 MHz. The 902-928 MHz band suffers from similar interference issues.

See 47 CFR 18 - Subpart C. 47 CFR § 18.301 Operating frequencies. ISM equipment may be operated on any frequency above 9 kHz except as indicated in § 18.303. The following frequency bands, in accordance with § 2.106 of the rules, are designated for use by ISM equipment:


  • 6.765 MHz - 6.795 MHz - center ISM frequency 6.78 MHz 6780 kHz
  • 13.553 MHz - 13567 MHz - center ISM frequency 13.56 MHz 13560 kHz - 22 meter band, also Part 15 allocation
  • 26.957 MHz - 27.283 MHz - center ISM frequency 27.12 MHz 27120 kHz - 11 meter band, shared with Part 15 and Part 95 (CB radio), RC, and data links/telemetry/paging
  • 40.660 MHz - 40.700 MHz - center ISM frequency 40.68 MHz - shared with Part 15 band
  • 902 MHz - 928 MHz - center ISM frequency 915.0 MHz - 33cm ham band
  • 2400 MHz - 2500 MHz - center ISM frequency 2450 MHz 2.45 GHz - very crowded 2.4 GHz band
  • 5725 MHz - 5875 MHz - center ISM frequency 5800 MHz 5.8 GHz band - not as crowded as 2.4GHz
  • 24.0 GHz - 24.25 GHz - center ISM frequency 24.125 GHz
  • 61.0 GHz - 61.5 GHz - center ISM frequency 61.25 GHz
  • 122.0 GHz to 123.0 GHz - center ISM frequency 122.5 GHz
  • 2400 GHz to 2500 GHz - center ISM frequency 2450 GHz



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