Abstract Developments are considered under the headings (i) connection techniques, (ii) control techniques, (hi) interaction of switching and transmission techniques, (iv) facilities offered, and (v) connecting network topology. In each topic, there are open questions. The major forecasts are: (i) the extensive use of electronic digital multiplex connecting networks, compatible with digital transmission systems; (ii) the introduction of optical connecting techniques, which offer both compatibility with optical transmission and some interesting new possibilities for the size and configuration of switches; (iii) the extensive use of stored program control; (iv) the supplementation of central processors by distributed control techniques for the common operational procedures, probably using microprocessors; and (v) the widespread use of semiconductor integrated circuits both for connection and control functions.