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REF ID:A600359 GOVERNMENT COMMUNICATIONS HEADQUARTERS U.S. Liaison Office 00/133/51 25 May 1951 TOP SECRET MEMORANDUM FOR
DIRECTOR, AFSA Subject:
French Modification of the M-209 Converter Ref: (a) AFSA
041811Z May 1951 (409) 1.
As instructed in the reference, I examined the modified M-209 converter in
Paris on 21 and 22 May. We agree in the conclusion that the
modification is well engineered and that its use is operationally
feasible. 2.
The modification consists of replacing the original fixed-slide normal
alphabet print and index wheels with demoutable print and index wheels
of approximately the same physical dimensions as the originals, and
that have radial slots in which metal type can be set so as to
provide any desired sequence on the wheels. For convenient
reference, Figure 1 describe the new type-wheel. 3.
Cost of the modification is about $24 per machine. The movable type print
wheel is covered by a French patent concerning which he indicated
there whould be no difficulty if other nations wanted to
modify their own machines. 4.
I think the proposed modification offer a great security and I believe it
is possible to consider the machine acceptable for NATO use at
third level, at least as an interim measure, subject to establishment
of satisfactory rules for use, such as bisection, frequent
change of alphabet and settings, good indicator system, etc. Use of
the machine by the French should increase the security of their
internal communications considerably. 5. The
Colonel Veyron LaCroix authorized me to bring a decryption GRIFFIN
CHILES Commander,
U.S. Navy U.S.L.O.
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