If you have lost your “Settings Protection” - Password on your D19C, please follow one of these 2 steps below to clear it.
Take the last four digits of the serial number and divide by 2. (Example: S/N: 25600 = > Password = 5600/2= 2800)
If your serial number is uneven, then please subtract first number or digit, and then follow the same as above. (Example: S/N: 25601 => Password = (5601-1)/2= 2800)