The Southwest Regional Laboratory Instructional Management System (IMS) utilizes a configuration of electronic data processing (EDP) equipment to transform instructional program performance data into instructional program management information. To perform this transformation, SWRL has selected a configuration consisting of on-site optical scanners, low-speed character printers, and a Data Concentrator which communicates with a large central processing system. System operation under each of four IMS-EDP models was simulated using IBM's General Purpose Simulation System (GPSS). The results are reported in terms of device utilization rates, system thruput time and system thruput capacity. They indicate the desirability of multiplexing and variable phasing for optimum system capacity and turnaround time. (Author)