- You may be looking for HADS, a defence mechanism in TARDISes.
A HAD robot was favoured to win a competition sponsored by an Earth president. The Seventh Doctor suspected that the robots were more than they seemed, so he and a 21st century girl tricked Perseus into buying a superior android. It disabled the AI blockers in all of Perseus' robots, preventing Perseus from gaining access to every household in the country. (PROSE: Anteus)