In '42 through '48 there were 3 Technician ranks in the U.S. Army, T/3, T/4 and T/5. T/5 as Corporal, T/4 as Sergeant, T/3 as Sergeant/Staff Sergeant with an altered pay scale to represent their speciality. Medics, Mechanics, Radio and other speciality areas were typically Technician were used. In those days they didn't have much authority to issue orders, but could be placed in second command under combat situations.