ISM band(redirected from Unlicensed spectrum)
ISM band(Industrial, Scientific and Medical band) A part of the radio spectrum that can be used for any purpose 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 titled 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. See U-NII.
Power LimitISM Bands (Watts)902 - 928 MHz Cordless phones 1 W Microwave ovens 750 W Industrial heaters 100 kW Military radar 1000 kW 2.4 - 2.4835 GHz Bluetooth 100 mW 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/ac 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 and WiGig)