What entity utilized the first practical, large-scale application of IVR technology for verification purposes?

AT&T’s Western Electric for credit card verification

The technology achieved its first practical, large-scale deployment through systems designed to handle credit card verification for AT&T’s Western Electric. This early application demonstrated the commercial viability of using automated input directly linked to backend processing systems. In this initial iteration, a caller would input required data, such as a credit card number, using DTMF tones, and the system would immediately respond with an automated acceptance or denial message. This proved that machines could efficiently manage routine transactional calls without requiring intervention from human operators, thereby establishing an immediate business use case for the nascent IVR concept.