The Special Fish Report
Albert W. Small (December 1944)
Codes and Ciphers
TOP SECRET Special Fish Report Page 110
In the schematic, keys have been numbered by me for convenience
in describing switching. They are not numbered on the real keyboard.
The "C" keys on the right operate the 5 counters.
The "E" and "S" keys on the left refer to the five impulses.
Suppose it is desired to count all the x x x x x characters
that result in delta D from running a Z tape against a wheel pattern.
The wheel pattern is selected on another board and switched to "delta;"
the Z tape switched to "delta;" and then on the keyboard shown (page 109)
keys E1, E2, E3, E4, and E5 thrown "down," and key C1 thrown "down".
That means that counter 1 will count all cases wherein impulses 1,2,3,4,and 5,
equal cross. If it is desired to count all the cases of . . . . . then keys
E1 E2 E3 E4 and E5 are thrown "up" and key C1 "down;" if it is desired to
count all the cases of x . . . . then keys E1 and C1 are thrown "down," and
keys E2, E3, E4, and E5 thrown "up." The counter keys are thus always thrown
down, to make counters operative; and the E keys are thrown up to make
an impulse dot or down to make an impulse cross.
Suppose a separate count is desired on x x . x x, x x x x x,
. . . . . and . . x . . then one way would be to throw keys: E1E2E4E5C1 down
E3 up; E6 E7 E8 E9 E10 C7 down; E11 E12 E13 E14 E15 up C13 down; E16 E17 E19
E20 up E18 C19 down; and the first pattern x x . x x would be counted by counter
1, the second by counter two, the third by counter 3, the fourth by counter 4.
Suppose it is desired to count positions wherein 1 plus 2 equals dot.
Keys S1 and S2 are thrown down (giving 1 plus 2) key R1 is thrown up (giving
"equals dot") and key C51 thrown down (giving "counter one to count such places.")
The S keys are thus used in summing. For (1p2)./(4p5). we would throw down
keys S1 S2; up key R1, down key C51; down keys S9 S10; up key R2; down key
C56. Thus counter 1 would have two conditions imposed upon it simultaneously:
that 1 plus 2 equal dot, and that 4 plus 5 equal dot.