SIM800L/Bridge/bridge.ino

// simple bridge between Raspberry Pi Pico's
// serial 1 and serial 2


#define S2_TX 8  // GP8, actual pin 11
#define S2_RX 9  // GP9, actual pin 12

UART Serial2(S2_TX,S2_RX,0,0);

void setup() {
  Serial.begin(9600);
  Serial2.begin(9600);
}

void loop() {
  while (Serial2.available() > 0) {
    Serial.print(Serial2.readString());
    delay(10);
  }
  while (Serial.available() > 0) {
    Serial2.print(Serial.readString());
    delay(10);
  }
}