TheCodeBreakers
men. From April, 1942, to the end of the war, its commanding officer was
the Signal Security Agency chief. When G-2 took operational control, the
battalion was redesignated the 9420th Technical Service Unit, which at
the end of the war became part of the Army Security Agency. By that
time, the original four radio circuits on which it was sending intercept
material back to Washington at the time of Pearl Harbor had swollen to
46 full-time radioteletypewriter channels.
The Army, like the Navy, established cryptanalytic units in the several
theaters of war. Their organization varied from one theater to another.
The South West Pacific Area, Under MacArthur, had at its headquarters
a communications-intelligence unit called the Central Bureau and in the
field a number of subordinate units. Central Bureau, or
I '
l^ll
simply C.B., had been founded in August of 1942 by Lieutenant
Colonel Joe R
annaabi.ee 
