Zither switch with open-wire multiple and two-motion ratchet drive, made by the Strowger Automatic Telephone Company, Indiana, United States, 1894.
This automatic selector switch was first used in the LaPorte (Indiana, USA) telephone exchange in autumn 1894. It used piano wire and a contact arm that could move in two directions to select the chosen wire. It was the first switch to use the basic mechanism that would be used in later step-by-step switches at telephone exchanges, and was proposed by the brothers John and Charles Ericsson. Its layout gave rise to the nickname 'zither' switch. The design was only used for a short time before it was replaced by the more familiar step-by-step switch.