Engineering extension course

From Memory Alpha, the free Star Trek reference

Engineering extension courses were a series of classes offered by Starfleet Medical Academy. They were designed to give students basic information about technology to supplement their medical training.

In 2370, Julian Bashir told Miles O'Brien about the engineering extension courses he took while they were hiding from Kellerun forces on T'Lani III. He offered to assist O'Brien with repairing a communications system, but O'Brien declined. (DS9: "Armageddon Game")