WP-001 · TELECOM · · 9 pp.
LTE Cat 1bis Retrofit of the Nokia 2190 Within the Original ABS Enclosure
A custom LTE Cat 1bis board, a VoLTE baseband, and an 18650 cell fitted entirely inside an unmodified Nokia 2190, retaining its keypad, membrane, and 1.3-inch window.
Abstract
This capability study documents the restoration of modern cellular function to the Nokia 2190, the North American GSM 1900 variant of the 2110 family, rendered inert by the shutdown of 2G networks. The architecture is a custom embedded system fitted entirely within the original ABS enclosure: an ESP32-S3 dual-core microcontroller, a SIMCom SIM7672G LTE Cat 1bis baseband providing single-antenna VoLTE, an ES8388 codec bridging the digital PCM interface to the original 32-ohm earpiece, and a Nordic nPM1300 PMIC managing a retrofit 18650 cell within the original battery housing.
The donor-transplant approach, extracting a motherboard from a modern feature phone, fails on first measurement: the 1.3-inch display window is fixed, the keypad matrix maps to nothing on the donor board, and the closed-source RTOS forecloses any software remedy. The custom board succeeds because the internal volume of the 2190 is, by modern standards, enormous. The original firmware aesthetic is reconstructed from reverse-engineered DCT-3 ROM assets. The objective is a single-purpose communications terminal. Construction has not been scheduled.
Acknowledgements
The premise originated in a discussion of three methods for restoring service to a Nokia 2190: relocation to a market where 2G remains active, deployment of a private cellular network, or reconstruction of the internal radio. This study pursues the third. Whether a handset engineered to finally receive calls is used to answer them remains outside its scope.
Keywords
- Nokia 2190
- SIM7672G
- LTE Cat 1bis
- ESP32-S3
- diode-multiplexed matrix
- DCT-3 firmware
- VoLTE
- hardware retrofit