Magneto

This device for generating electricity was often found in early telephones. Usually housed in an oak box with a handle protruding out of one side. When the handle was turned, the gear on the right would drive a smaller gear (below it) that would generate a current flow in the telephone system, ringing an operator who would answer and then connect the caller to the destination desired. After their phone use was over these would often end up in science or physics classrooms and demonstration aids, sometimes they were disassembled for the powerful horseshoe magnets (the five black bars in the above image.)

My grandmother used one of these phones up until the late 1960s when her phone system went to touch-tone, skipping the rotary dial era completely.

I had a rotary phone even in the early 90s (!) but we had to get a touch tone phone when playmates of the children who came over couldn’t call home—they had never seen a dial phone.