RX-8 modulator

RX-8 modulators were used in the legs of Imperial AT-ATs to control the signals that made the legs move.

In 1 ABY, the Rebel Alliance was looking into developing jamming devices that could interfere with the AT-AT's locomotion. When Droma Ordo learned that people working for Lady Valarian had recovered the leg of an AT-AT, he sent a Rebel agent to infiltrate the Valarian Depot and remove the modulator from the leg to analyze its circuitry. The schematics were sent back to Ordo.

Text and facts from the “RX-8 modulator” article on Wookieepedia, licensed under CC BY-SA 3.0. Modified for this site.