Remreed Switching Networks for No. 1 and No. 1A ESS: Remreed Switches

The major apparatus development undertaken for the No. 1 ESS remreed project was the design of a series of new crosspoint switches. The goals of the new switch development were to produce designs that would be both smaller and more economical than their ferreed forerunners. These goals were met by taking advantage of the new 238A sealed contact to increase the crosspoint packing density and by designing the overall switch structure to allow for the maximum use of automatic manufacturing techniques. The increased crosspoint packing density allowed by the 238A sealed contact is due to two factors. First, the reduced physical dimensions 537 of t h e new 238A sealed contact led to a corresponding reduction in t h e dimensions of the new crosspoint. Second, the reduction in t h e a m o u n t of permanent magnetic material utilized in each crosspoint reduced the magnitude of stray magnetic fields and, hence, the total interference field felt by any crosspoint due to surrounding nearest neighbors is small. In combination, these factors resulted in an intercrosspoint spacing of 0.450 in. and led to the design of switches t h a t contain as m a n y as twice the number of crosspoints as conventional ferreed switches, yet consume less frame area and less total volume. This design philosophy is one key to the cost savings a t t r i b u t e d to t h e remreed switch technology. T h e creation of switches having 128 crosspoints rather t h a n t h e conventional 64 reduces the cost per crosspoint of m a n y common manufacturing steps.