Abstract :
The evolution of long-distance line-communication systems and the problems associated therewith are outlined. Attention is drawn to the need for certain international standards which facilitate the interconnection of such systems, and the work of the C.C.I.F. in this direction is mentioned. The evolution of radio-relay systems forming parts of internal telecommunication networks is traced, and the salient characteristics of modern systems are summarized. Emphasis is put on the need for international agreement on the preferred characteristics of radio-relay systems to facilitate their interconnection among themselves and with line-communication systems, The work of the C.C.I.R. in this field is mentioned, and the view is expressed that preferred characteristics should be adopted in the near future even though they may need to be reviewed, and perhaps revised and extended, after a number of years have elapsed.
