Relay tower

A relay tower, or relay beacon, was an electrically powered structure meant to receive, reinforce, or retransmit a broadcast or program over long distances without a physical connection between one or more people. Several of such devices were located on the Outer Rim planet of Serenno, used by the charismatic Sith Lord Count Dooku to transmit messages from his palace to his affiliates on and off the battlefield during the Clone Wars.

Text and facts from the “Relay tower” article on Wookieepedia, licensed under CC BY-SA 3.0. Modified for this site.