Telecommunications, or telecom, is the transmission of signals over long distances. It began with the invention of the telephone in 1876, then expanded to radio broadcasts in the late 1800s and to television in the early 1900s. Today, telecommunications also includes the Internet and cellular phone networks.
Early telecommunications transmissions used analog signals, which were transferred over copper wires. Today, telephone and cable companies still use these same lines, though most transmissions are now digital. For this reason, most new telecommunications wiring is done with cables that are optimized for digital communication, such as fiber-optic cables and digital phone lines.
Since both analog and digital communications are based on electrical signals, transmitted data is received almost instantaneously, regardless of the distance. This allows people to quickly communicate with others across the street or across the globe. So whether you're sending an e-mail to a coworker, or talking on the phone with a friend, you can thank telecommunications for making it possible. It sure is more efficient than the Pony Express.