A communications relay was a type of space structure with mounted sensor arrays manufactured by Arakyd Industries. They were commonly set up as deep space network stations used by the Galactic Empire.
Relays were found near communications satellites.
Prior to the Battle of Endor, Imperial defector Zaletta used a relay Comm Center to divert messages and inform the Rebel Alliance of Imperial activity. A skirmish was initiated in order to trace Zaletta.