RIP-5 Code Machines
Prior to the beginning of the “On-The-Roof Gang” training, intercept operators copied Japanese radio messages by hand. In 1924, LT Safford, the renowned Father of Naval Cryptology, designed specifications for a special typewriter that would facilitate the intercept and transliteration of Japanese Kata Kana code by the “On-The-Roof Gang.”
Through consultations and negotiations with the Underwood Typewriter Company, Safford ordered four of these “Underwood Code Machines,” giving them the Navy designator RIP-5. This modified typewriter allowed intercept operators to use a typical American keyboard layout to print Kata Kana characters during intercept operations. The intercept operator would type an English letter that coincided with the Kata Kana code character heard, and the Japanese Romaji would be represented on the paper.
Acquisition of the RIP-5 units continued through the 1920’s and 1930’s. The first few went directly to intercept sites in China, Guam, and the Philippines. Between 1928 and 1930, OP-20G purchased sufficient RIP-5’s to fully outfit the intercept stations as well as the “On-The-Roof” training classroom. Even though the classroom was fully equipped with nine RIP-5 Underwood Code Machines by the end of 1930, students were still required to show complete proficiency in the copying of the Kata Kana code by hand before moving on to the RIP-5.
Eventually, an updated portable model of the RIP-5 was developed for use by intercept operators on Radio Intelligence Units (RIU) deployed on board ships. Later the RIU operations became known as Direct Support.