Principles of connection control in an electronic telephone exchange by the use of magnetic drums

The paper describes some functions of storage within a telephone exchange, and, in particular, the application of a magnetic drum to this storage in an electronically controlled time-division-multiplex telephone exchange. It serves as an introduction to supporting papers relating to the methods of application within a particular exchange system. There is discussion of the methods of use of the drum and of the types of circuits employed with it in the logical manipulation of the stored information.