The signal regulation for leg movement in Imperial AT-ATs was achieved through the use of RX-8 modulators within the legs.
During 1 ABY, the Rebel Alliance explored the possibility of creating jamming devices to disrupt the AT-AT's mobility. Upon discovering that people under the employ of Lady Valarian had obtained an AT-AT leg, Droma Ordo dispatched a Rebel operative to infiltrate the Valarian Depot. The mission was to extract the modulator from the leg for circuit analysis, with the resulting schematics then forwarded to Ordo.
Prior to its shutdown on December 15, 2011, RX-8 modulators were featured in the 2003 video game Star Wars Galaxies. This massively multiplayer online roleplaying game was created by Sony Online Entertainment and distributed by LucasArts.