The manual presents technical information on the computer assisted teacher training system (CATTS) which aims at developing a versatile and economical computer based teacher training system with the capability of providing immediate analysis and feedback of data relevant to teacher pupil transactions in a classroom setting. The physical configuration of CATTS consisting of three interdependent stations (teaching, observation-coding, and analysis-encoding) is described. Hardware components (coding, computer, and output) of the prototype CATTS are graphed and discussed. It is explained that the basic control element in the CATTS system is a small digital computer which is programed to provide system timing, information collection, and feedback of results. Three variations of the basic system are considered including a consensus coding system, a simultaneous coding system, and CATTS with tally pattern recognition. Discussed are current hardware and software extensions of CATTS in the areas of data collection and input developments, extensions of the real-time multi-observer system, and feedback and output developments. Related research in the establishment of a general training laboratory is considered. (GW)