ISM Industrial, Scientific and Medical Radio Bands

The ISM radio bands are radio bands (portions of the radio spectrum) reserved internationally for the use of radio frequency (RF) energy for industrial, scientific and medical purposes other than telecommunications. Examples of applications in these bands include radio-frequency process heating, microwave ovens, and medical diathermy machines. The powerful emissions of these devices can create electromagnetic interference and disrupt radio communication using the same frequency, so these devices were limited to certain bands of frequencies. In general, communications equipment operating in these bands must tolerate any interference generated by ISM applications, and users have no regulatory protection from ISM device operation.

ISM bands
  • Type A. The use of these frequency bands for ISM applications shall be subject to special authorization by the administration concerned, in agreement with other administrations whose radiocommunication services might be affected. In applying this provision, administrations shall have due regard to the latest relevant ITU-R Recommendations.
  • Type B. Radiocommunication services operating within these bands must accept harmful interference which may be caused by these applications.

Low High Center frequency Type
6.765 MHz 6.795 MHz 6.78 MHz A
13.553 MHz 13.567 MHz 13.56 MHz B
26.957 MHz 27.283 MHz 27.12 MHz B
40.66 MHz 40.7 MHz 40.68 MHz B
433.05 MHz 434.79 MHz 433.92 MHz A
902 MHz 928 MHz 915 MHz B
2.4 GHz 2.5 GHz 2.45 GHz B
5.725 GHz 5.875 GHz 5.8 GHz B
24 GHz 24.25 GHz 24.125 GHz B
61 GHz 61.5 GHz 61.25 GHz A
122 GHz 123 GHz 122.5 GHz A
244 GHz 246 GHz 245 GHz A

In spite of the real purpose of ISM bands, there has been rapid growth in its use in low-power, short-range communications platforms. Bluetooth devices, cordless phones, Wi-Fi computer networks, and NFC devices all make use of ISM bands. In 1985, the U.S. Federal Communications Commission opened the ISM bands for use in mobile communications and wireless LANs. In 1997, it incorporated supplementary bands in the 5 GHz range, referred to as the Unlicensed National Information Infrastructure (U-NII). The HIPERLAN wireless LANs of Europe make use of the same 5 GHz bands known as the Broadband Radio Access Network.

Wireless LAN devices using ISM bands
  • Bluetooth 2450 MHz band falls under WPAN
  • HIPERLAN 5800 MHz band
  • IEEE 802.11/Wi-Fi 2450 MHz and 5800 MHz bands
  • IEEE 802.15.4, ZigBee and other personal area networks may use the 915 MHz and 2450 MHz ISM bands because of frequency sharing between different allocations.