Inside are some things you’d expect, like a SIM800 GSM module for the telephony part, and an ESP32 to count the pulses from the dialer and communicate between it and the GSM module. But it also ...

He decided to go with the low-cost SIM800L GSM modem, but as it only works on 2G networks, provisions have been made in the board design to swap it out for a more modern module should you desire.

While the best unlocked phones almost certainly support GSM carriers like AT&T and T-Mobile, it’s best to look for devices that work with all the major U.S. providers, including Verizon.

Main Camera Triple 50 MP, f/1.4-f/4.0, 23mm (wide), 1/1.31", 1.2µm, dual pixel PDAF, OIS 50 MP, f/2.0, 75mm (telephoto), PDAF (10cm - ∞), OIS, 3.2x optical zoom ...

Body Dimensions 165.9 x 76.2 x 8 mm (6.53 x 3.00 x 0.31 in) ...