Which retail technology was FIRST widely implemented in military exchanges (PX/BX) before becoming common in civilian retail stores?

Military Post Exchanges (PX) and Base Exchanges (BX) have evolved from simple commissaries to full-service retail operations supporting troops worldwide. These unique retail environments have adapted distinctive technologies and marketing approaches to serve military personnel and their families. Test your knowledge about how these specialized retail operations have developed alongside military history and the innovations they've pioneered.

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Standardized barcode scanning systems (1974)
Self-checkout kiosks (1992)
RFID inventory tracking (1981)
Contactless payment systems (1997)