TheCodeBreakers
As the meaning of a codegroup became known in
the Combat Intelligence Unit, whether through its own efforts or by a
helpful message from another unit, the codegroup and its meaning were
punched on an I.B.M. card and stored in the machine. When an intercept
came in, a clerk would punch its codegroups on I.B.M. cards and feed
them in. The machine automatically made the run of repeated
subtractions and the check of its mechanized difference "books"
necessary to find the identical remainders, and then, with human
guidance, the runs to reconstruct the relative additive sequence, correct
it to the absolute sequence, and strip it from the encicode message. This
machine would then compare the placode groups with the decode cards
in its storage and print out the plaintext for whatever decode cards it
had. Presumably it would also print out the various possibilities in the
case of garbled or partial codegroups. It could also make frequency
annaabi.ee 
