ISM Bands (Industrial, Scientific, and Medical):

Purpose: ISM bands are radio frequency bands designated by the International Telecommunication Union (ITU) for use by industrial, scientific, and medical devices that emit radio frequency energy as part of their operation.

Regulation: Devices operating within ISM bands typically do not require a license for operation, allowing for easier deployment of wireless technologies.

Global Allocations: ISM bands are allocated globally, meaning that they are available for use in all ITU regions.

Frequencies: Common ISM bands include:

• 2.4 GHz band: 2400-2483.5 MHz
• 5 GHz band: Various sub-bands within 5150-5850 MHz range
• 915 MHz band: 902-928 MHz

Each ITU region has its own set of regulations, frequency allocations, and coordination mechanisms tailored to the specific needs and characteristics of the countries within that region. These regions serve as frameworks for international cooperation and collaboration in the field of wireless communications, ensuring interoperability and compatibility of wireless devices across borders. 

ITU Region 1 (863-870 MHz):

• Covers Europe, Africa, the Middle East (including Western Asia and the Persian Gulf), and the former Soviet Union countries.

ITU Region 2 (902-928 MHz):

• Encompasses North and South America, including Greenland and some of the Caribbean islands.

ITU Region 3 (779-787MHz):

• Includes Asia (except for Western Asia and the Persian Gulf), Australasia, and the Pacific islands.