The society in and around Kaldor City was apparently almost wholly dependent on humanoid robots as servants and for manual labour. The Sandminers which made a major contribution to Kaldor's economy were almost entirely crewed by robots of this type.
Although superficially similar (all, for example, designed to be aesthetically pleasing), the robots were constructed in a number of classes which varied in their intelligence, autonomy, and ability to communicate.
Standard Robot Classes
The majority of the robots were D-class Dums, so named because they were constructed without the ability to speak. On a Sandminer the Dums apparently mostly kept to the engineering decks away from the human crew, making them appear less common than was in fact the case. Dums wore black tunics. D84 was disguised as one of them.
More able were the V-class Voc robots, who had the power of speech. In the absence of humans, Vocs performed essential control deck duties on a Sandminer and were capable of running the vehicle without organic supervision. They wore green tunics.
Each Sandminer's complement of robots included one SV-class Super-Voc, which had enhanced decision-making and organisational skills. The Super-Voc was effectively the leader of the robots, though still of course subservient to any of the authorised human crew. The Super-Voc wore a silver tunic.
Only one UV-class Ultra-Voc was ever constructed, as an even more intelligent and autonomous version of the standard SV. It is not known what colour it was clothed in.
SASV-1 was another unique robot, an attempt to improve on a specialised SV class unit numbered D84. However, SASV-1 was based on plans drawn up by Taren Capel and proved mentally unstable.