Untitled

#include <SoftwareSerial.h>
SoftwareSerial gsm(8, 9); // RX, TX

void setup() {
  Serial.begin(9600);
  gsm.begin(9600);
  Serial.println("Type AT commands:");
}

void loop() {
  if (gsm.available()) Serial.write(gsm.read());
  if (Serial.available()) gsm.write(Serial.read());
}