Which retail technology advancement was FIRST implemented in military exchanges (PX/BX) before becoming widespread in civilian retail?

Military exchanges and post/base exchanges (PX/BX) have been vital retail operations serving military personnel and their families for centuries. These unique retail environments have evolved dramatically with technology, pricing strategies, and product offerings. This poll explores the intersection of military history and retail operations, focusing on how these specialized stores have shaped military life and adapted to changing times.

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Barcode scanning systems (1974)
Magnetic stripe ID card verification for purchases (1967)
Electronic point-of-sale terminals (1979)
Computerized inventory management systems (1982)