ISM stands for Industrial, Scientific and Medical. The ITU (International Telecommunication Union) had originally reserved a portion of the RF spectrum globally for industrial, scientific and medical applications.

The use case was followed initially, however over the years, the use of the ISM Bands become more widespread for short-range, low power wireless communications systems like cordless phones, WiFi, Bluetooth, NFC and a host of other short range wireless applications.

ISM Frequency Bands