What is a Dongle?
A dongle is a small piece of hardware designed to protect software. It can come in various forms, commonly either USB or parallel port. The dongle for the original DCT4 unlock code calculators was a parrallel port device. If the dongle was not plugged into the LPT port of your computer the software would not run. The actual program code that calculated the unlock codes was actually stored in a small micro chip within the dongle. The software itself only acted as a front end and retrieved the codes from the dongle itself.
If you have a 3650 locked to AT&T (USA) use the following network codes to calculate the correct unlock code:
Use network code 24407 if your IMEI starts with: 351102500
Use network code 31038 if your IMEI starts with: 351102501
Use network code 31038 if your IMEI starts with: 351102502
Use network code 31038 if your IMEI starts with: 351102503
For 3650 AT&T USA always use code 1 out of the 7 generated!