Abstract: A portable, hand-held data terminal for scanning and reading a bar code that includes a removable scanning head that can be secured to the terminal in one orientation for right-handed operation, and can be removed and secured to the terminal in an opposite orientation for left-handed operation. The scanning head includes a bottom panel having a tab and slot structure, and the terminal includes a top panel having a tab and slot structure. The positions of the slots of the top panel structure allow the tabs of the scanning head structure to be inserted between and then under the tabs of the top panel structure in a locked configuration.