why got occured error (1600) when instal ios 6 on iphone 3g

Hi dbs5852,

Thanks for using Apple Support Communities. This article has information on error 1600 and may help:

Resolve specific iTunes update and restore errors

http://support.apple.com/kb/ts3694

Check USB connections

If there’s an issue with the USB port, cable, dock, or hub, or if the device becomes disconnected during restore, try troubleshooting the USB connection, then troubleshooting your security software.

Common errors: 13, 14, 1600-1629, 1643-1650, 2000-2009, 4000, 4005, 4013, 4014, 4016, “invalid response”, and being prompted to restore again after a restore completes.

To narrow down the issue, you can also change up your hardware:

• Use another USB cable.
• Plug your cable into a different USB port on your computer.
• Try a different dock connector (or no dock).
• Add (or remove) a USB hub between your device and computer.
• Connect your computer directly to your Internet source, with no routers, hubs, or switches.

If you see your error after changing your USB connections, continue to the next section to troubleshoot your hardware.

Cheers,

- Ari