What device used electrical signals to transmit messages quickly over long distances?

The telegraph was a groundbreaking invention during the 19th century that utilized electrical signals to convey messages rapidly across extensive distances. It revolutionized long-distance communication, allowing for the instantaneous transmission of information compared to other methods such as postal services, which could take days or even weeks.

Invented by Samuel Morse and others, the telegraph used a series of dots and dashes (Morse code) to represent letters and numbers, enabling messages to be sent and received over wires connecting telegraph stations. This technology played a crucial role in various sectors, including business, journalism, and even military operations, as it allowed for quick and efficient communication that was previously unavailable.

While the other devices listed, such as the telephone, radio, and satellite, also contributed significantly to communication advancements, they came after the telegraph and operate on different principles and technologies. The telephone transmits voice communication, the radio uses electromagnetic waves to broadcast audio signals without the need for wires, and satellites facilitate global communication and information transmission through space.