problem at intermediate relay points, all TOP SECRET and RESTRICTED DATA traffic (approximately three per cent) was encrypted off-line. The fourth problem listed previously as one prevailing during Operation IVY concerned the overloading of the Eniwetok telephone exchange and cable plant facilities. Two position, 220 line, non- multiple Kellogg switch boards were employed but peak calling rates were far greater than the operators could satisfactorily handle. Further, it was found during both GREENHOUSE and IVY that the two principal cables serving the south end of Eniwetok were filled al- most to capacity resulting in a lack of flexibility and a shortage of spare pairs. These inadequacies became more important when it was announced that the Air Force Task Group would be located on Eniwetok Island for Operation CASTLE, Following a study of plausible solutions to the telephone exchange problem, it was decided to employ a 400-line dial exchange. Monetary savings obtained by the smaller number of operating personnel required offset the initial cost of the dial exchange while rapid, efficient service and the capability of handling widely fiucuating traffic loads greatly improved telephone service, The Sig- nal Corps Plant Engineering Agency engineered the project, procured the equipment, and provided an experienced team to acccmpiish the installation, Change-over to the new system was made on 30 December 1953 and telephone service during Operation CASTLE was outstanding. Plans for expansion of the outside cable plant began on 7 July 1953 when OCSigO was requested to authorize and establish a Class 209