A self-checking system of supervisory control

This paper describes a new type of supervisory control system which was developed to reduce the selection time in large, multistation applications. The principles are based on the use of short and long electrical pulses and circuit designs not requiring a check-back code for assuring accuracy. It is equally applicable to a two-wire telephone line or a carrier-current channel. The design is quite flexible, permitting many alterations and additions to satisfy local conditions peculiar to its problems. The theory behind the elimination of the check or selection is explained.