Who Is Calling Me?

In the beginning when there were only a few operators sending Morse code they could be identified by their unique “fists” or particular sounds or techniques from each operator. Obviously, as communication increased, both by wire as in railroads and over the air for shipping and commercial usage, a system was needed to identify each sender or station.
The International Telecommunications Union (ITU) has regulations which outline the basic principles used in forming amateur call signs. In the United States, The FCC oversees the assignment of American call signs in accordance with the ITU. Every U.S. amateur radio station call sign is a combination of a 1 or 2 letter prefix, a number, and a 1, 2, or 3 letter suffix. The first letter in the U.S. is always an A, K, N, or W. The number usually, but not always, designates the geographical area of the station. The FCC now allows vanity call signs to be applied for which can confuse the original intent of the system. Special event call signs are usually short and do not fit this pattern. My call sign, K8ASA breaks down to K = U.S.A., 8 = Ohio, ASA is my vanity for the Army Security Agency who taught me Morse code 50 years ago.
Your call sign is very important. It belongs to your station alone. You are required to identify yourself, either CW or voice, at the end of each transmission and also at intervals of not more than 10 minutes during a transmission. More call sign rules are covered in the ARRL Operating Manual.
This is one time when you can be proud to have been assigned an identifier by the U.S. government. Use it with honor and respect.