Vintage Phone Goes LTE
Meet RotaryCell, a hand-wired prototype that turns old rotary phones into portable cellular devices
The RotaryCell project has achieved a significant milestone with the creation of a working hand-wired prototype that converts a traditional rotary telephone into a self-contained, battery-powered, portable cellular telephone. This innovative project uses an ESP32-S3 controller, a LilyGO T-A7670G-S3 Standard board, and a Silvertel AG1171 subscriber-line interface to enable the rotary phone to work over LTE.
The project's design ensures that the original telephone remains unmodified, with the added electronics mounting reversibly inside the case. The working prototype can be carried and operated away from a fixed telephone connection, making the original desk telephone usable at meetings, demonstrations, or anywhere compatible cellular service is available.
The RotaryCell project uses a single protected 21700 cell for power and features adjustable transmit/receive audio conditioning through the Audio and Reset A4 PCB. The project repository was updated on August 28, 2026, with the current firmware version being v0.10.4.
## What's Next The first integrated PCBs, including the AG1171 Carrier Through-Hole PCB ordered from JLCPCB on August 28, 2026, are currently awaiting assembly and validation. The project repository provides a complete point-to-point wiring and component reference, allowing others to recreate the proven hand-wired prototype.
## Why It Matters The RotaryCell project demonstrates the potential for innovative reuse of traditional technology, enabling the conversion of outdated devices into functional, modern communication tools. This project's success could inspire further experimentation and development in the field of retro technology revival, making old devices relevant again in the modern era.
The project's progress and documentation are publicly available, allowing others to follow and potentially contribute to the development of this unique technology. As the project continues to evolve, it will be interesting to see how the RotaryCell concept is received and whether it will inspire a new wave of innovation in the tech community.
