The Starfleet Technical Services Academy is a training facility for enlisted Starfleet personnel. It is located on Mars. Alfonse Pacelli was a graduate of the academy. (TNG: "Eye of the Beholder")
An okudagram readout of Pacelli's personnel file was displayed on a viewscreen that Deanna Troi was studying. Some of the facts could be called into question since she was involved in a very detailed hallucination when the data was shown. Presumably this is a branch of Starfleet Academy attended by candidates to become enlisted personnel, as Pacelli was a non-commissioned officer after his graduation.