Cryptologic Bytes

The History of the Cryptologic Technician (CT) Rating

In this guest post on, John Gustafson,  CTRCM (ret) explores the history of the Cryptologic Technician (CT) rating. See an excerpt below and then visit to read the full post.

Today’s Cryptologic Technicians can trace their roots back to those enterprising Radiomen who taught themselves the Japanese Kata Kana code in the early to mid 1920s and established the first intercept station at Shanghai, China.

During the summer of 1927, five Marines attended Kata Kana training in Shanghai and in September 1927 were transferred to Peiping where, under the leadership of CRM Dorman A. Chauncey, established the second radio intercept station.

The Marine detachment in Peiping performed the first known temporary deployment of Communications Intelligence personnel when two Marine operators, along with Chief Chauncey, deployed aboard the USS Trenton (CL-11), and two additional Marine operators deployed aboard the USS Memphis (CL-13) for the entire month of September 1928.  Presumably this mission was to copy traffic from Japanese fleet exercises.

The success of these early intercept operations led to the establishment of a permanent school on the roof of the Main Navy building on Constitution Avenue in Washington DC where especially qualified Radiomen were trained to intercept and analyze foreign radio communications.  During the 12 year life of this school at least 176 (150 Navy and 26 Marine), enlisted radio operators received their training.  This group became know as the On the Roof Gang (OTRG).  Many of these graduates formed the nucleus of the communications intelligence operations in the Pacific at the beginning of World War II.



Visit the "On this Date in History" calendar to learn about important events in cryptology and other related fields.