Wio LTE (ATコマンドを使ってみた） ref: http://qiita.com/KazuyukiEguchi/items/4a366394faf15467209c

test.ino

#include <WioLTEforArduino.h>

#define EC21J Serial1

WioLTE Wio;

void setup() {
  delay(200);

  SerialUSB.println("");
  SerialUSB.println("--- START ---------------------------------------------------");

  SerialUSB.println("### I/O Initialize.");
  Wio.Init();

  SerialUSB.println("### Power supply ON.");
  Wio.PowerSupplyLTE(true);
  delay(5000);

  SerialUSB.println("### Turn on or reset.");
  if (!Wio.TurnOnOrReset()) {
    SerialUSB.println("### ERROR! ###");
    return;
  }

  delay(3000);

  SerialUSB.println("Loop Start");
}

void test_time2()
{
  EC21J.write("AT+CCLK?");
  EC21J.write(0x0d);

  delay(1000);

  while (EC21J.available() > 0) {
    SerialUSB.write(EC21J.read());
  }
}

void loop() {
  test_time2(); 
  delay(5000);
}