They were used by telephone, telegraph, power and railroad companies. The first insulators had no threads to screw them down on the pole pins. They were mounted by pressing them down on a square of burlap on top of the pins. read more
The Model 202 was the first telephone created in the 1930s. The Model 202 was an oval-shaped phone that was connected to a dial block. The Model 202 was mostly used by companies and was mainly a desktop phone. read more
Early telephones were technically diverse. Some used liquid transmitters which soon went out of use. Some were dynamic: their diaphragms vibrated a coil of wire in the field of a permanent magnet or vice versa. read more