This paper describes an effective microprocessor-based CAI system which has been repeatedly tested by a large number of students and edited accordingly. Tasks not suitable for microprocessor based systems (authoring, testing, and debugging) were handled on larger multi-terminal systems. This approach requires that the CAI language used on the microprocessor-based system either be identical to the language used on the authoring system or be a subset of that language. WTS-PILOT-BASIC, described in the appendix, is the current language combination developed and used in the system. The resulting system is available in two versions: one which implements all of WTS PILOT and BASIC with floating point, the four arithmetic operations, two-dimensional numeric arrays, and the standard set of BASIC string operations; and a full version with a complete set of scientific functions, string arrays, and disk-read and disk-write capabilities. (VT)