Without the table showing what words go with which numbers, it would be very hard to guess the meaning of the encoded message. For this reason codes have been used for thousands of years by people to protect private messages. Codes are not used only to protect secret information. Certain codes, like Morse Code , were developed before the radio and the telephone to make it easy to send messages great distances. The telegraph allowed a single tone, or beep, to be sent through a wire to a remote location.
Morse code translates the letters of the alphabet into a series of short or long beeps.
For example, an A is sent as a short beep followed by a long beep. Messages were sent letter by letter across the telegraph wire as many long and short beeps. Morse code could also be used to allow two ships to communicate through the use of blinking signal lights. Even today Morse code is still used in radio because the beeps sometimes can get through heavy static that voice communications cannot. The table that contains the translation of the words to the code is often in the form of a book and is referred to as a codebook.