photophone

The photophone was an early communication device invented by Alexander Graham Bell in 1880 that transmitted voice signals using light instead of electrical wires. It works by converting sound into modulated light beams, which travel through the air to a receiver that reconverts the light back into sound. Essentially, it used sunlight or other light sources to carry voice messages wirelessly, making it an important step toward modern optical communication technologies like fiber optics. While it wasn't widely used at the time, the photophone demonstrated the potential of light-based wireless communication.