Abstract: A system for simulating changes in the resistance of a living body includes an output interface circuit including a variable resistance adapted to smoothly and naturally simulate the resistance of a living body. A generator circuit includes a microprocessor under the control of software to play back digitally recorded data representative of patterns of changing resistance. The software includes a user selection feature permitting various patterns to be played back in a way that simulates changes in the resistance of living body useful for learning about the patterns.

Abstract: A special broadcast communication link is provided between a central processing unit and plural computer peripheral devices, the communication link being in addition to normal data and addressing communication lines, and providing a distributed control channel which is used to inhibit selected classes of interrupt signals from controllers associated with the peripheral devices in accordance with an interrupt classification system. This communication channel permits the central processing unit to issue a data command which selectively inhibits the peripheral devices from issuing selected classes of interrupt signals.