With example code, this article covers ESP32 SIM7600 4G LTE cellular modem interfacing using Arduino IDE. Hardware used is ESP32 Gateway.
ESP32 PPPoS modem “esp_modem_dte_send_cmd(): process command timeout” error, causes, and some solutions that work with SIM7600 and A7670.
Using multiple SIM cards with SIMCom or Quectel modems is easy using multiplexers and a basic logic controller. Modems must support hot swap.
I list some cases with using SIM commands like AT+CIMI which result in “ERROR: SIM failure”. Common problems are listed along with solutions.
ESP32 4G modem interface allows you to add cellular internet connectivity to your IoT designs. Find schematics, PCB guidelines and code here.