SHP-DH537 - How to perform a factory reset

1. Unlock and open the door
2. Take the battery cover off
3. Press and hold the [REG] button for 5 seconds or until the second set of beeps are heard
   • Ding Dong -> Dingding 
4. Enter factory reset code + * 
   • 4560852580 : Factory reset without wireless module connection
   • 1470852369 : Factory reset including wireless module connection
   • Success : Ding Dong Deng
   • Fail : Dingdongdingdong