Quantity   Component name
1 × Western Electric 500-series telephone Donor rotary telephone retaining its original dial, handset, switchhook, network block, mechanical ringer, wiring, and case.
1 × LilyGO T-SIM7670G-S3 Standard ESP32-S3 controller and A7670G LTE voice modem.
1 × Silvertel AG1171 Subscriber-line interface that operates the telephone’s original analog circuitry and mechanical ringer.
1 × RotaryCell Audio/Reset A4 PCB Custom PCB providing adjustable audio conditioning and hardware modem power-cycle control.
1 × RotaryCell AG1171 carrier PCB Custom carrier connecting the AG1171 to the controller, telephone network block, and power system.
1 × Samsung 58E 21700 cell Flat-top, 5330 mAh lithium-ion cell powering the completed telephone.
1 × USB-C breakout board Charging connector using only V+ and GND. Requires a USB-A-to-USB-C cable because the board lacks USB-C PD request resistors.
1 × 3D-printed RotaryCell mounts Internal carriers for the LilyGO, Audio/Reset PCB, AG1171 carrier, and rear USB-C connector.
1 × Through-hole components and wiring Resistors, capacitors, diode, headers, JST connectors, stranded wire, and the external 1 µF microphone-reference capacitor.
1 × Activated cellular voice SIM Physical SIM with compatible cellular voice service.