What are ISM Radio Bands?

ISM in this context stands for Industrial, Scientific, and Medical. ISM bands are portions of the radio spectrum reserved for non-telecommunication applications internationally. They are typically used for short-range, low power wireless communication in industrial, scientific and medical devices. But all of them may not be of low power. For example, microwave ovens, magnetic resonance imaging and medical diathermy machines use significant RF power. These can disrupt radio communication using same frequency. They can also interfere with medical devices using these frequencies for communication like cardiac pacemakers. Hence appropriate shielding is needed for such devices. In general, if communications equipment operate on the ISM bands, they must tolerate any interference generated by ISM applications. Users have no regulatory protection from ISM device operation on these bands.

Other devices which may use the ISM bands are cordless phones, bluetooth devices, near-field communication devices, garage door openers, baby monitors and wireless computer networks. These devices are not generally considered as ISM devices. International Telecommunication Union has allocated frequencies in multiple bands for ISM applications. They are in the region of 6, 13, 26, 40, 433 and 902 MHz as well as in the region of 2.4, 5,7, 24, 61, 122 and 244 GHz. Though some of these are worldwide, some are subject to local acceptance. Some of these frequencies are shared with amateur service and amateur satellite service. Yet others are shared with other services depending on the administration involved.