Telephoning using Light and Solar Energy

New telephone systems have been installed by the Deutsche Bundespost on lines vulnerable to lightning in the Bavarian mountains. Initially eleven mountain huts were linked to the valley by these communication links. Light plays an important parts in these installations in two different ways: The transmission paths are optical waveguides, and the power is supplied by solar cells. Now that this type of subscriber line has given excellent service for five years, the DBP is to set up further facilities on a large scale.