!'2!!~~1.~ - ~liRkll>.rF sEC=ijifff ft-IFORMATION 

_Office Memorandum · oNITEn sTATEs aovERNMENT 

TO : J.~r. Friedman, AFSA-OOT DATE: 9 May 1952 

FROM Mr. Cor!""J, AFSA-4ll 

SUBJECT: 

~Pl'ON ROAD~ To S1..1.DE" N~ 2'38 

This chart shows a reakdown b;r security classification of the traffic fron Haopton Roads Port of Embarkation to Algiers, North Africa, for the 

~onth of April, 1944. Three definite peaks in traffic volurae are evident, each 

of which inQic~tes a convoy moveJTlent from Hampton Roads to Algiers. The approximate size of a movem~nt is judged from the totals of messages and groups in 

the peak period, while the destination and route are eiven away by addressee 

call signs int.he messages. Close inspection will show the first traffic surge 

began on 4 April, the second on 13 April, and the last on 22 April. Experience 

has shown that these traffic peaks a~pear on the circuit a day or two followine 

the actual convoy sailing date. The convoy movements are therefore ncalledn on 

the 2nd, 11th and 2oth of April. Furthermore, the traffic study shows definitely the proportions of s1_1pplies and troops carried in each convoy. This is 

due to the f~ct that all passenger nessages are classified SECRET; cargo messaees are CONFIDfilTTIAL. Detailed analysis shows that there were 21,836 

CONFmENTIA!:. groups, and 3,965 SEX::RET groups tr.:msmitted in connection with the 

2 April convoy. The next convo~ gave rie~ to 16,160 CONFIDEUTIAL and 4J470 

SECRET groups. The third convoy required 19J429 CONFJDENTIAL groups and 594 

SECRET groups. It is apparent from these figures that the major function of 

each of these convo;?s was to carr<J equipment and supplieW 

0 I( 

· . CONFEHENCE:i- 5L \J)\?° N~ Z~~ C Thi8Cfliirt50ws the da~r traff'ic •rolume addressed to the Presidential 

Conference call sign in Nover.:iber and DeceMber, r943, at the time of the Cairo 

and Teheran Conferences. The attention of t.he Traffic Analysis Unit in Washington was directed to this traffic for fnur reasons. First, the traffic was 

addressed to a new call sign; second, the traffic bore a new system indicator; 

third, the traffic was largely of lJRGEIIT precedence; and fourth, traffi_c to 

the now call sign was routed over different channels on various days. The figures for 11 November through 16 November, 1943 when traffic was routed over the 

Cairo, Accra, and Oran circuits--represent arranee~ents ~~at were made in preparation for the President's arrival. Therenfter, the traffic was routed to 

the particular headquarters through which the President was passing. B-.! following the routings of th.J call sign, it wo,~ possjhle to trace the President's 

trips fron Oran through Algiers to Cairo, then to Teheran (traffic to Teheran was 

routed via Asmara communicRtion facilities), back to Cairo, and through Algiers, 

Cran, Dakar, Trinidad, and San Juan on the homeward trip • .J 

This chart, then, indicates how information about an activity may be disclosed by traffic flow and external characteristics. 

If I may be of further assistance, 

CGNRDIEHTtA• -

please let me know. 

/ 

~rry Head, Transmission 

eclassified and approved for 

elease by NSA on 05-09-2014 

ursuantto E .0. 13526