having issue with unlock instructions

I am having an issue with step 3.  when I power my device on with a non ATT sim card, I donot get the display to enter the unlock code

1. Power off the device, remove the battery, and insert a non-AT&T SIM card.

2. Re-insert the battery and power on the device with non-AT&T SIM.

3. The device displays \"Enter the device unlock code.\"

4. Enter the unlock code.

5. Press OK.