Published online by Cambridge University Press: 01 January 2025
The wiring of the plugboard of the IBM type 405 machine for the computation of sums of squares and cross products of positive and negative numbers is described. The method makes greater demands on the X distributor and class selector capacity of the machine than does the method of wiring the plugboard when the numbers all have the same sign.
Essentially the same wiring, except for the use of two-position X distributors, is briefly described by H. R. J. Grosch in “Harmonic Analysis by the Use of Progressive Digiting,” Proceedings of the Educational Research Forum, 1946, p. 82