Founded in 1960 as Quindar Electronics Incorporated, QEI was an early adopter of solid-state technology for industrial applications with the introduction of the first transistorized voice frequency (audio tone) telemetry products for electric network monitoring and control applications. Quindar rapidly became the leading supplier of such products to the electric utility and the transit industry. With the advent of integrated circuits later in the decade, QEI introduced a full function SCADA system, the Quindett III, which was widely deployed in electric utility applications and became one of the first applications of a modern SCADA system in public transit at SEPTA. The Quindett system included full-function SCADA RTU utilizing high noise immunity integrated circuits. This first generation RTU also utilized a reliable control subsystem with Select Before Operate (SBO) logic to assure correct point selection and current sensing to detect multiple relay operations.