The document is a system documentation manual of the Computer-Assisted Teacher Training System (CATTS) developed by the Center for Innovation in Teaching the Handicapped (Indiana University). CATTS is characterized as a system capable of providing continuous, instantaneous, and/or delayed feedback of relevant teacher-student interaction data to a trainee in the classroom in order to modify behavior through regulatory teaching moves. Chapter 1 discusses rationale, the importance of immediate feedback, observation systems in teacher training programs, computer technology in teacher education, preservice research and development activities with CATTS, and other training applications of CATTS. Described in chapter 2 are the component systems (CATTS stations, data flow, data collection, data analysis, feedback, storage and retrieval) and an observation system training subsystem. Chapter 3 provides a technical overview and detailed descriptions of CATTS constituent systems, including design configuration, and hardware and software systems. Chapter 4 deals with the hardware components of the system (central processing component, input hardware, output hardware, and support hardware components). The software operating system components are described in chapter 5, including data collection, data storage and transmission, device handlers, console command control, program development, and program loaders. The final chapter offers conclusions relating to technical experience with CATTS, reliability of CATTS functions, cost-effectiveness, and CATTS technical future. The appendix provides the command list and data file formats. (BD)