Cannot get AT response on SIM7600

[navidkashi]

I'm using LilyGo SIM7600 and the esp-iot-bridge to share internet access from LTE modem to WiFi clients. I configured the TX, RX, and power pin in sdkconfig and used extended DCE, but when module turned on this error appeared in LOG. It seems that module doesn't response to AT command.

I (20884) bridge_modem: ==================================== I (20884) bridge_modem: ESP 4G Cat.1 Wi-Fi Router I (20885) bridge_modem: ==================================== I (20892) uart: queue free spaces: 256 E (21399) esp-modem-dte: esp_modem_dte_send_cmd(255): process command timeout response timeoutem_dce: esp_modem_dce_generic_command(31): Command:AT I (21404) sim7600_board: Current timeouts: 1 and errors: 0 E (26411) esp-modem-dte: esp_modem_dte_send_cmd(255): process command timeout W (26411) esp_modem_dce: esp_modem_dce_generic_command(31): Command:+++ response timeout E (26916) esp-modem-dte: esp_modem_dte_send_cmd(255): process command timeout response timeoutem_dce: esp_modem_dce_generic_command(31): Command:AT E (26924) esp-modem-dte: esp_dte_handle_line(87): handle line failed E (26930) esp-modem-dte: esp_dte_handle_line(87): handle line failed

[tswen]

Ensure that the 4g module is reset after the chip is up. If the 4g module is not reset, or the AT communication is initiated before the 4g module is completely reset, the AT communication failure will occur. Can be connected to MODEM_ RESET_ The reset pin from GPIO to 4g module can also be reset manually. In addition, the waiting time after reset should be adjusted according to the actual reset time of the module. https://github.com/espressif/esp-iot-bridge/blob/master/components/iot_bridge/src/bridge_modem.c#L38