Highly reliable transmission-checking scheme for digital data links

The paper gives a classification of transmission errors that can affect a binary digital data-transmission system, with a discussion of methods of detecting such errors. Feedback checking offers high security with minimum transmission redundancy. A practical transmission-checking scheme, incorporating feedback, is described, intended for use over short or medium distances. The security provided by this scheme against all classes of transmission error is high, and obtainable without degradation of data-transmission efficiency.