PPP_WIFI_BRIDGE.ino

#include <PPP.h>
#include <WiFi.h>

#define PPP_MODEM_APN "internet"
#define PPP_MODEM_PIN "0000"  // or NULL

// WaveShare SIM7600 HW Flow Control
#define PPP_MODEM_RST       25
#define PPP_MODEM_RST_LOW   false  //active HIGH
#define PPP_MODEM_RST_DELAY 200
#define PPP_MODEM_TX        21
#define PPP_MODEM_RX        22
#define PPP_MODEM_RTS       26
#define PPP_MODEM_CTS       27
#define PPP_MODEM_FC        ESP_MODEM_FLOW_CONTROL_HW
#define PPP_MODEM_MODEL     PPP_MODEM_SIM7600

// SIM800 basic module with just TX,RX and RST
// #define PPP_MODEM_RST     0
// #define PPP_MODEM_RST_LOW true //active LOW
// #define PPP_MODEM_TX      2
// #define PPP_MODEM_RX      19
// #define PPP_MODEM_RTS     -1
// #define PPP_MODEM_CTS     -1
// #define PPP_MODEM_FC      ESP_MODEM_FLOW_CONTROL_NONE
// #define PPP_MODEM_MODEL   PPP_MODEM_SIM800

// WiFi Access Point Config
#define AP_SSID "ESP32-ETH-WIFI-BRIDGE"
#define AP_PASS "password"

IPAddress ap_ip(192, 168, 4, 1);
IPAddress ap_mask(255, 255, 255, 0);
IPAddress ap_leaseStart(192, 168, 4, 2);
IPAddress ap_dns(8, 8, 4, 4);

void setup() {
  Serial.begin(115200);
  Serial.setDebugOutput(true);

  // Listen for modem events
  Network.onEvent(onEvent);

  // Start the Access Point
  WiFi.AP.begin();
  WiFi.AP.config(ap_ip, ap_ip, ap_mask, ap_leaseStart, ap_dns);
  WiFi.AP.create(AP_SSID, AP_PASS);
  if (!WiFi.AP.waitStatusBits(ESP_NETIF_STARTED_BIT, 1000)) {
    Serial.println("Failed to start AP!");
    return;
  }

  // Configure the modem
  PPP.setApn(PPP_MODEM_APN);
  PPP.setPin(PPP_MODEM_PIN);
  PPP.setResetPin(PPP_MODEM_RST, PPP_MODEM_RST_LOW, PPP_MODEM_RST_DELAY);
  PPP.setPins(PPP_MODEM_TX, PPP_MODEM_RX, PPP_MODEM_RTS, PPP_MODEM_CTS, PPP_MODEM_FC);

  Serial.println("Starting the modem. It might take a while!");
  PPP.begin(PPP_MODEM_MODEL);

  Serial.print("Manufacturer: ");
  Serial.println(PPP.cmd("AT+CGMI", 10000));
  Serial.print("Model: ");
  Serial.println(PPP.moduleName());
  Serial.print("IMEI: ");
  Serial.println(PPP.IMEI());

  bool attached = PPP.attached();
  if (!attached) {
    int i = 0;
    unsigned int s = millis();
    Serial.print("Waiting to connect to network");
    while (!attached && ((++i) < 600)) {
      Serial.print(".");
      delay(100);
      attached = PPP.attached();
    }
    Serial.print((millis() - s) / 1000.0, 1);
    Serial.println("s");
    attached = PPP.attached();
  }

  Serial.print("Attached: ");
  Serial.println(attached);
  Serial.print("State: ");
  Serial.println(PPP.radioState());
  if (attached) {
    Serial.print("Operator: ");
    Serial.println(PPP.operatorName());
    Serial.print("IMSI: ");
    Serial.println(PPP.IMSI());
    Serial.print("RSSI: ");
    Serial.println(PPP.RSSI());
    int ber = PPP.BER();
    if (ber > 0) {
      Serial.print("BER: ");
      Serial.println(ber);
      Serial.print("NetMode: ");
      Serial.println(PPP.networkMode());
    }

    Serial.println("Switching to data mode...");
    PPP.mode(ESP_MODEM_MODE_CMUX);  // Data and Command mixed mode
    if (!PPP.waitStatusBits(ESP_NETIF_CONNECTED_BIT, 1000)) {
      Serial.println("Failed to connect to internet!");
    } else {
      Serial.println("Connected to internet!");
    }
  } else {
    Serial.println("Failed to connect to network!");
  }
}

void loop() {
  delay(20000);
}

void onEvent(arduino_event_id_t event, arduino_event_info_t info) {
  switch (event) {
    case ARDUINO_EVENT_PPP_START:     Serial.println("PPP Started"); break;
    case ARDUINO_EVENT_PPP_CONNECTED: Serial.println("PPP Connected"); break;
    case ARDUINO_EVENT_PPP_GOT_IP:
      Serial.println("PPP Got IP");
      Serial.println(PPP);
      WiFi.AP.enableNAPT(true);
      break;
    case ARDUINO_EVENT_PPP_LOST_IP:
      Serial.println("PPP Lost IP");
      WiFi.AP.enableNAPT(false);
      break;
    case ARDUINO_EVENT_PPP_DISCONNECTED:
      Serial.println("PPP Disconnected");
      WiFi.AP.enableNAPT(false);
      break;
    case ARDUINO_EVENT_PPP_STOP: Serial.println("PPP Stopped"); break;

    case ARDUINO_EVENT_WIFI_AP_START:
      Serial.println("AP Started");
      Serial.println(WiFi.AP);
      break;
    case ARDUINO_EVENT_WIFI_AP_STACONNECTED:    Serial.println("AP STA Connected"); break;
    case ARDUINO_EVENT_WIFI_AP_STADISCONNECTED: Serial.println("AP STA Disconnected"); break;
    case ARDUINO_EVENT_WIFI_AP_STAIPASSIGNED:
      Serial.print("AP STA IP Assigned: ");
      Serial.println(IPAddress(info.wifi_ap_staipassigned.ip.addr));
      break;
    case ARDUINO_EVENT_WIFI_AP_PROBEREQRECVED: Serial.println("AP Probe Request Received"); break;
    case ARDUINO_EVENT_WIFI_AP_STOP:           Serial.println("AP Stopped"); break;

    default: break;
  }
}