Switching Networks of Planar Shifting Arrays

Switching machines in the Bell System have grown in both number and capacity to meet the growing traffic demand. Early machines consisted of a small amount of distributed logic embodied in electromechanical devices but, as technology has permitted, the machines have evolved into largely solid state systems with central processor control. The environment in which switching machines must operate has also changed from a relatively small collection of analog voice grade circuits to an overwhelming number of circuits of various bandwidths with an increasing proportion of digital facilities. It is the purpose of this paper to look at a possible future realization of one portion of a switching machine that might have advantages in meeting future requirements in a largely digital environment. We may consider that a switching machine consists of three major subdivisions. One is a switching network, which makes cross connections for each call. A controller, used to direct the operation of the network, is another. Finally, some interface is needed between the network, the controller, and external circuits. The subject of this paper is a switching network, one that may reduce the complexity of the tasks of the other two subdivisions of a switching machine as well as have advantages of its own in conjunction with some emerging technologies. 991