Alexander Graham Bell demonstrated the telephone at Philadelphia’s 1876 Centennial Exposition.
Bell’s exhibit presented his early telephone technology during the international fair. The device transmitted speech electrically, building on earlier work in telegraphy and Bell’s experiments with sound and speech. The demonstration helped attract public attention to a technology that was still unfamiliar to most visitors.
Bell had received a U.S. patent for the telephone in March 1876, only months before the exposition opened. The famous fair therefore became an important showcase for the invention during the same year as America’s first centennial.
The telephone is sometimes confused with the telegraph because both used electrical signals. A telegraph generally transmitted coded messages, while Bell’s telephone was designed to carry the sound of a person’s voice. The exposition also featured other important technologies, including sewing machines and typewriters.