Telegraph is the earliest reliable real-time long-distance communication method to transmit information by electricity. Its inventor is Samuel Morse, who is called the father of the telegraph.

The telegraph invented by Samuel Morse was patented in the United States on 1837. 1844, Morse sent the first telegram in human history from Washington to Baltimore. In the packed Capitol, Morse used his trembling hands to control the telegraph he had worked hard to develop for more than ten years.

Telegraph information is sent in the form of electrical signals through special exchange lines. This signal uses a code instead of words and numbers, and the commonly used code is Morse code. With the popularization and application of telephone and fax, telegrams are rarely used.