CW has strong anti-interference ability and can use less power to transmit longer distances like the digital transmission. but its disadvantage is very time-consuming. it is because the original sentence in words is translated into Morse code When transmitting, it takes several to ten times longer than speaking these words, which seriously affects the communication efficiency. Words with many letters are also prone to errors.
In order to improve communication quality and communication efficiency, people have invented and used various abbreviations in long-term practice, which is to abbreviate frequently used words and sentences in communication to one or a few letters. It has evolved and perfected and formed the abbreviation that is now commonly used internationally. There are two common rules for commonly used English abbreviations.
N-North；aa-all after；gb-good bye ；