I found a different group that represents SIS. Wasn’t sure if anyone had posted this one.
https://en.wikipedia.org/wiki/Signal_Intelligence_Service
The Signal Intelligence Service (SIS) was the United States Army codebreaking division, headquartered at Arlington Hall (former campus of Arlington Hall Junior College for Women, founded 1927 to 1942, on Arlington Boulevard in Arlington, Virginia, across the Potomac River from Washington, D.C.). It was a part of the U.S. Army Signal Corps so secret that outside the office of the Chief Signal officer, it did not officially exist. SIS was an early predecessor to the modern National Security Agency (NSA) and later appropriated by the National Security Council who reappointed the resources into the modern NSA.
Thank you Good research.