An Experimental Switching System Using New Electronic Techniques

Following recent activities in switching research 1,2 and the development of new solid state devices, engineering studies indicate t h a t a telephone switching system using new electronic techniques is practicable. An experimental electronic switching system designed and built for laboratory purposes is described in this paper. Other articles will present the various parts of the system in more detail (e.g., Refs. 3, 4 and 5). Earlier papers have outlined many of the techniques which are available in electronic switching, 6,7 and the particular choices which were made for this experimental system have been publicized. 8 A brief review is given here. The experimental system may be said to have a space-division electronic switching network for telephone connections, in which the connections themselves are made under the direction of time-division (oneat-a-time) common control. Large-capacity temporary and semipermanent electronic storage units fulfill most of the memory requirements of the system. The time-division control uses a program stored in the semipermanent memory. This program specifies the manner in w:hich an office will function on various types of calls and provides various service features. Since a photographic memory medium is used in the semipermanent memory, the operating features of the office may be changed readily. 1091