ISM band - technical definition

(Industrial, Scientific and Medical band) A part of the radio spectrum that can be used by anybody without a license in most countries. In the U.S., the 902-928 MHz, 2.4 GHz and 5.7-5.8 GHz bands were initially used for machines that emitted radio frequencies, such as RF welders, industrial heaters and microwave ovens, but not for radio communications.

In 1985, the FCC Rules (Part 15.247) opened up the ISM bands for wireless LANs and mobile communications. In 1997, it added additional bands in the 5 GHz range under Part 15.407, known as the Unlicensed National Information Infrastructure (U-NII). Europe's HIPERLAN wireless LANs use the same 5 GHz bands, which are entitled the "Broadband Radio Access Network."

Numerous applications use the ISM/U-NII bands, including cordless phones, wireless garage door openers, wireless microphones, vehicle tracking and amateur radio.

   ISM Bands           Power Limit

   902 - 928 MHz
   Cordless phones          1 W
   Microwave ovens        750 W
   Industrial heaters     100 kW
   Military radar        1000 kW

   2.4 - 2.4835 GHz
   Wi-Fi - 802.11b/g        1 W
   Microwave ovens        900 W

   5 GHz
   5.725 - 5.825 GHz        4 W
   Wi-Fi - 802.11a/n


   U-NII 5 GHz Bands
   Wi-Fi - 802.11a/n

   5.15 - 5.25 GHz        200 mW
   5.25 - 5.35 GHz          1 W
   5.47 - 5.725 GHz         1 W
   5.725 - 5.825 GHz        4 W


   60 GHz Band
   57 - 64 GHz (see WirelessHD)