Unlocking of Alcatel X600D modem is possible with an NCK code if it asks for NCK after changing the default SIM card. Means, if your X600D has uncustomized firmware then it can be easily unlocked with correct code. Once the dongle is unlocked you can use all SIM cards (supported bands) around the world.
How to unlock Alcatel X600D?
1. Put any unacceptable SIM card in your data card.
2. Connect to PC USB port.
3. Open My Computer >> Virtual CD-ROM.
4. Install in PC.
5. Now launch the X600D software from desktop shortcut.
6. It will ask for NCK / SIMlock / Unlock code.
7. Enter the correct code which is provided by routerunlock.com.
8. Click OK.
9. Now your device is unlocked permanently.
Note: Unlock / NCK code of Alcatel X600D is not free.