A been largely supplanted by fiber-optic cables.

A microwave link is a communications system that uses a beam of the radio wave in the microwave frequency range to transmit information between two fixed locations on the earth. They are crucial to many forms of communication and impact a broad range of industries. Broadcasters use microwave links to send programs from the studio to the transmitter location, which might be miles away. Microwave links carry cellular telephone calls between cell sites. Wireless Internet service providers use microwave links to provide their clients with high-speed Internet access without the need for cable connections. Telephone companies transmit calls between switching centers over microwave links, although fairly recently they have been largely supplanted by fiber-optic cables. Companies and government agencies use them to provide communications networks between nearby facilities within an organization, such as a company with several buildings within a city.
One of the reasons microwave links are so adaptable is that they are broadband. That means they can move large amounts of information at high speeds. Another important quality of microwave links is that they require no equipment or facilities between the two terminal points, so installing a microwave link is often faster and less costly than a cable connection. Finally, they can be used almost anywhere, as long as the distance to be spanned is within the operating range of the equipment and there is the clear path (that is, no solid obstacles) between the locations. Microwaves are also able to penetrate rain, fog, and snow, which means bad weather doesn’t disrupt transmission.
In a microwave link, the transmitter produces a microwave signal that carries the information to be communicated. That information the input can be anything capable of being sent by electronic means, such as a telephone call, television or radio programs, text, moving or still images, web pages, or a combination of those media.