A telegraph is a communication system that sends information by making and breaking an electrical connection. Telegraphy is the long-distance transmission of messages where the sender uses symbolic codes, known to the recipient, rather than a physical exchange of an object bearing the message. The word telegraph is derived from the Greek words tele, meaning “distant,” and graphein, meaning “to write” . The electrical telegraph was the first electrical telecommunications system and the most widely used point-to-point text messaging system from the 1840s until the late 20th century. The telegraph was developed in the mid-19th century and for more than 100 years was the principal means of transmitting printed information by wire or radio wave. The telegraph machine that can send messages from a typewriter-like keyboard and print incoming messages in readable text with no need for the operator to interpret the message was called a teleprinter. The telegraph is the forerunner of all communication systems today, and many of the principles developed for the telegraph are still in use in modern communication and computer networks.