The ISM band: A review of the essentials

In 1985 the Federal Communications Commission issued rules permitting “ intentional radiators” to use the “ Industrial, Scientific and Medical (ISM) Bands ( 902-928, 2400-2483.5, 5725-5850 Mhz) at power levels of up to one Watt without end-user licenses. Originally these bands had been reserved for unwanted, but unavoidable emissions from industrial and other processes, but they also supported a few ( often military) communications users. The new rules led to the development of a large number of consumer and professional products and is considered to be an important step towards the development of wireless computing or multimedia applications. Applications in the ISM band include, wireless LANs, short range links for advanced traveller systems ( electronic toll collection), garage door openers, home audio distribution, cordless phones, private point to point links, remote control, wireless telemetric systems ( e.g electrical power consumption monitoring) etc. Applications seem to be limited by the imagination rather than technology. A drawback of the ISM band is lack of any protection against interference. In particular microwave ovens limit the useful range of such communications devices. The techteam at Signal Processing Group Inc. recently released a brief whitepaper on the ISM band. Interested readers can find this under the “Engineer’s Corner” menu item in the SPG website located at

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