RotaryCell turns an old rotary telephone into something you can carry away from the phone line and use over a cellular network. The original handset, dial, switch hook and mechanical bell remain intact: dial a number normally and it places a mobile call; receive one and the old bell rings.

Maker fregacmols fits an ESP32-S3, cellular modem, battery and circuitry that imitates the telephone exchange the vintage phone expects. Rather than teaching the 1950s hardware new behavior, the project miniaturizes enough of its old infrastructure to make the phone feel at home on LTE.