In this embodiment, CPU system 34 (see FIGS. 1, 5 and 6) may be disposed internal to shoe 10, or may be an external CPU (not shown) coupled to shoe 10 via an I/O port 56 (see FIGS. 11, 12, 16 and 17), and coupled in turn to the optical scanner 41 and to other components of the present invention, including keyboards and LCD displays.