Aayla Secura's beacon transceiver. The Jedi beacon transceiver functioned as an encoded subspace receiver. Jedi Order members carried this device, which enabled them to get signals and transmissions originating from the Jedi Temple located on Coruscant.
These beacon transceivers were compact, portable units featuring a display screen alongside a communications transceiver. The transceiver was capable of receiving transmissions either from the Jedi beacon on Coruscant itself, or from a Jedi's own personal comlink. In urgent situations, a Jedi could transmit Emergency Code Nine Thirteen, which would be picked up by any beacon transceiver within range, requesting immediate aid. Furthermore, these devices also received signals for recall and retreat from the Temple, particularly when HoloNet channels had been compromised.
When Coruscant came under attack by the forces of General Grievous, Yoda sent a recall message to every Jedi transceiver.
During the unfolding of Order 66, Darth Vader, having seized control of the Jedi Temple, reprogrammed the Jedi beacon to summon all Jedi back home, directly into the prepared ambush that awaited them at the Temple. Every surviving Jedi received this high-priority signal on their transceivers. However, Jedi Masters Obi-Wan Kenobi and Yoda successfully infiltrated the Temple after Vader departed for the Mustafar system. Kenobi then recalibrated the beacon, sending a warning to all Jedi to avoid Imperial Center.