Oklahoma will have to get used to a new telephone area code, but won't have to change their phone numbers.

The Oklahoma Corporation Commission voted 2-1 on Monday in favor of an "overlay" plan for the new 539 area code. New customers and phone lines will be assigned the new 539 area code no earlier than April 1, 2011, while existing customers will keep their current 918 area code numbers. Commissioners Bob Anthony and Jeff Cloud voted for the plan while Dana Murphy opposed it.

The area now served by the 918 area code includes metropolitan Tulsa and is expected to run out of telephone numbers sometime in the second quarter of 2012.