The specialty mark of the Coast Guard’s Telecommuni-cation Specialist (TC) rating—four “sparks” or lightning bolts pointing to the front—was first used in 1908 for the U.S. Revenue Cutter Service’s Electrician and Electrician First Class ratings. These two ratings were given unique marks following the establishment of the Coast Guard in 1915, with the latter being designated First Class Electrician and retaining the insignia.
In the early 1920s, the distinct specialty mark was designated for the new rating of Radioman (RM), established in both the Coast Guard (1920) and Navy (1921). Following the United States entry into World War II, the insignia was also worn by Radio Technicians (RT) until the war’s end.
Several specialties were available in the Radioman rating, including Teletype Repairman, Communication Security Equipment Operator (CSEO), Radio Operator (High Speed), Amateur Radio Operator, and Advanced Radioman. In 1971, the Teletype Repairman and CSEO specialties were discontinued, those functions being assigned to personnel in the Telephone Technician rating.
To address the expansion of communication methods available on Coast Guard ships and at shore installations, the RM rating was redesignated Telecommunications Specialist in 1994. But the inexorable merger of text and speech communications enabled by digital technology meant this new designation was too narrow to address operational needs, and in 2003 the TC rating was merged with the Quartermaster (QM) and Radarman (RD) ratings to create the Operations Specialist (OS) rating.