[Source] Summoning chips were a type of specialized chips that could send summon signals, telling their owners to contact those who sent those signals. They were equipped with a micro-screen and a transponding antenna to receive the signals. Darth Sidious used such devices during the Invasion of Naboo when he needed to summon his Trade Federation allies. It was speculated that Sidious had developed the chips, and had them installed in transceivers awarded to his underlings. Sidious' apprentice Darth Tyranus also used them to communicate with key members of the Separatist Council during the Clone Wars.