Detail of waveguide inside indoor unit:

​​​​​​​Sevillana de Electricidad was the first electrical company to use microwave links in its communications. The Borbolla Central had to be connected to the Sub. Santiponce, where the Regional Electrical Grid Maneuver Dispatch was maintained. Voice and data services were maintained in the 7 GHz band and with a capacity of 12 channels for many years.

Brown Boveri HK 418973 / 18 dlm – (Brown Boveri is part of the current ABB company)

Below, detail.