A control node was a unit which controlled a group of robotic constructs.
Groups of Clockwork Droids were led by control nodes. Without the control node, Clockwork Droids were unable to function and shut down. One such control node was the Half-Face Man, who over the course of millions of years had integrated human physiology into his makeup, (TV: Deep Breath) and the group of Clockwork Droids previously encountered by the Tenth Doctor had possessed their own control node. (TV: The Girl in the Fireplace [+]Loading...["The Girl in the Fireplace (TV story)"])
A Nolvox control node capable of controlling an entire army's worth of battle drones was one of the dangerous items placed on the Dr Smith shelf by Liz Haggard when she headed P.R.O.B.E.. It was stolen in November 2020 by Magister1971. (WC: Doctor X [+]Loading...["Doctor X (webcast)"])