To apply digital transmission to the distribution of television program material it is necessary to encode both sound and picture signals, protect them from the effects of transmission errors and multiplex them into a form suitable for the transmission link that is to be used. Coding, error protection and multiplexing have all received extensive study but their combined application in a system has received little discussion in the literature. This paper shows how a system was designed for a particular experimental application with a specified total bit rate. Particular emphasis is given to the multiplexing arrangements, including the necessary use of justification techniques. The equipment designed has been used in successful field trials of digital transmission by both cable and satellite.