On either side of the border, there are three stations, each with a microphone, speaker and tuning wheels that control a searchlight, that can be seen from a 50-kilometre radius. When your light beam intersects with someone else's in the sky, a two-way audio connection opens up and you can talk to the other person through the microphone. " CBC
SOURCE: ArtsJournal at 02:36PM on November 25, 2019