The Andorian Guard was a branch of the Federation Starfleet. The Guard was responsible for defense and maintained its own fleet of starships. Its chief, Admiral Thy'lek Shran, was one of the five chiefs of staff of the nascent Starfleet. The insignia was a stylized letter in Andorii, of the Andorian languages. (ENT - Rise of the Federation novel: A Choice of Futures)