A portable, hand-held data collection terminal unit is of modular structure including among other modules a display screen module, a keyboard module and a base module, each of which may be chosen from a plurality of modules available for assembly into the terminal unit. Consequently, a wide combination...http://www.google.ca/patents/US5202817?utm_source=gb-gplus-sharePatent US5202817 - Hand-held data capture system with interchangeable modules
