A converter has a casing and a plug. The casing has a mounting recess, multiple position posts, multiple conductive slices and multiple mounting protrusions. The mounting recess is formed in the casing. The position posts are formed on and protrude from the mounting recess. The conductive slices are mounted around the position posts. The mounting protrusions are formed on the mounting recess. The plug is detachably mounted on the casing and has an escutcheon, an engaging protrusion and multiple terminals. The escutcheon covers the mounting recess. The engaging protrusion is formed on the escutcheon, is mounted in the mounting recess and has a position groove and multiple holding grooves. The position is annular formed in the engaging protrusion and is mounted around the position posts. The holding grooves are formed on the engaging protrusion and engage the mounting protrusions. The terminals are formed on the escutcheon.