CEEFAX: Evolution and potential

Suitably equipped domestic television receivers and the existing television channel which feeds them were used to provide an extra service of written news and other information to the viewer. The development of the CEEFAX information broadcasting system to the end of a two-year experimental period is described. The background to the choice of transmission and display parameters is given, together with details of laboratory and field experiments. Particular emphasis is given to the selection of the addressing and coding systems to give reliable reception throughout the normal television service area. The basis for the choice of the many supplementary facilities of CEEFAX, such as color and graphics, is presented together with indication of the provisions made for future expansion in the use of CEEFAX.