The design of the CAI interface described is based on the microprocessor in order to meet three basic requirements for providing appropriate instruction to the developmentally handicapped: (1) portability, so that CAI can be taken into the customary learning environment; (2) reliability; and (3) flexibility, to permit use of new input and output devices as they are required and become available. The precise configuration of the terminal is determined by its use, and a number of special features are available, e.g., double size characters for use by the partially sighted, special graphic characters, animation, color, synthetic speech, and control of a random access slide projector. Input devices that may be used include a number pad, light pen, and touch sensitive display. Special devices for students with physical handicaps include the POSSUM apparatus, which may be controlled by a variety of binary switching devices, and the POSSUM Expanded Keyboard, both of which have been used by cerebral palsied students. Other special keyboards are designed to simplify the coding required for response, e.g., the "money" keyboard for social arithmetic problems. The terminal has also been developed into a stand-alone computer for use in areas without access to a host computer. (CHC)