SHP-DH537 - How to change the master PIN code

1. Unlock and open the door
2. Take the battery cover off
3. Press the [REG] button to start registration : Ding Dong
4. Enter the master pin code (default is 1234) + *
   • Success : Ding Dong Deng, Ding ding
   • Failed : Dingdongdingdong (If it’s wrong)
5. Enter  0 + * 
6. Enter the new master pin code + *
   • Success : Ding Dong Deng
   • Failed : Dingdongdingdong (if it’s same as current master PIN code or less digits)