What are the ISM frequency bands and which should be used?
The most commonly used ISM bands are referred to as the 900MHz, 2.4GHz and 5.8GHz bands. All permit the use of license-free spread spectrum radios within them. Generally, the 900MHz band is used in the Americas. The 2.4GHz band is used (with differing power constraints) throughout most of the world. While there are some differences between the characteristics of the two bands, the 900MHz band typically allows for higher power and longer distance transmissions while the 2.4GHz band, with its wider bandwidth, allows for higher data rates. In Europe, the 869 MHz and 433 MHz bands are also classified as ISM bands and China has opened the 220MHz band to license-free radios. The key consideration in terms of usage is most often determined by geographic location.
