Tagged: ISM bands
November 4, 2015 at 2:20 pm #7126
The industrial, scientific and medical (ISM) radio bands are radio bands (portions of the radio spectrum) reserved internationally for the use of radio frequency (RF) energy for industrial, scientific and medical purposes other than telecommunications. Examples of applications in these bands include radio-frequency process heating, microwave ovens, and medical diathermy machines. The powerful emissions of these devices can create electromagnetic interference and disrupt radio communication using the same frequency, so these devices were limited to certain bands of frequencies. In general, communications equipment operating in these bands must tolerate any interference generated by ISM equipment, and users have no regulatory protection from ISM device operation.
Despite the intent of the original allocations, and because there are multiple allocations, in recent years the fastest-growing uses of these bands have been for short-range, low power communications systems. Cordless phones, Bluetooth devices, near field communication (NFC) devices, and wireless computer networksall use frequencies allocated to low power communications as well as ISM, although these low power emitters are not considered ISM.
The ISM bands are defined by the ITU-R in 5.138, 5.150, and 5.280 of the Radio Regulations. Individual countries’ use of the bands designated in these sections may differ due to variations in national radio regulations. Because communication devices using the ISM bands must tolerate any interference from ISM equipment, unlicensed operations are typically permitted to use these bands, since unlicensed operation typically needs to be tolerant of interference from other devices anyway. The ISM bands share allocations with unlicensed and licensed operations; however, due to the high likelihood of harmful interference, licensed use of the bands is typically low. In the United States, uses of the ISM bands are governed by Part 18 of the Federal Communications Commission (FCC) rules, while Part 15 contains the rules for unlicensed communication devices, even those that share ISM frequencies. In Europe, the ETSI is responsible for governing ISM bands.
The ISM bands defined by the ITU-R are:
Regulatory authorities may allocate parts of the radio spectrum for unlicensed communications that may or may not also be allocated as ISM bands.
Frequency range Bandwidth Center frequency Availability 6.765 MHz 6.795 MHz 30 kHz 6.780 MHz Subject to local acceptance 13.553 MHz 13.567 MHz 14 kHz 13.560 MHz Worldwide 26.957 MHz 27.283 MHz 326 kHz 27.120 MHz Worldwide 40.660 MHz 40.700 MHz 40 kHz 40.680 MHz Worldwide 433.050 MHz 434.790 MHz 1.74 MHz 433.920 MHz Region 1 only and subject to local acceptance 902.000 MHz 928.000 MHz 26 MHz 915.000 MHz Region 2 only (with some exceptions) 2.400 GHz 2.500 GHz 100 MHz 2.450 GHz Worldwide 5.725 GHz 5.875 GHz 150 MHz 5.800 GHz Worldwide 24.000 GHz 24.250 GHz 250 MHz 24.125 GHz Worldwide 61.000 GHz 61.500 GHz 500 MHz 61.250 GHz Subject to local acceptance 122.000 GHz 123.000 GHz 1 GHz 122.500 GHz Subject to local acceptance 244.000 GHz 246.000 GHz 2 GHz 245.000 GHz Subject to local acceptance
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