D-class Dums were robots built by the Kaldor Company. They were built without the ability to speak and more simplistic mental abilities. On a sandminer, the Dums mostly kept to the engineering decks, away from the human crew, making them appear less common than was the case. Dums wore black tunics. D84, a highly sophisticated Super-Voc class robot, was disguised as a Dum. (TV: The Robots of Death)
A large number of Dums worked on the wards at the Kaldor City Hospital. However, Liv Chenka noted that Volar Crick had more Dums working at his private house. (AUDIO: Love Me Not)