OKLAHOMA CITY -- In a vote Monday morning, the Oklahoma Corporation Commission voted 2-1 on how it is going to break up the 918 area code.  

After holding a public discussion, the commissioners decided for the overlay option.

The commission had two choices, overlay or split. 

With the overlay plan, all existing numbers will keep the 918 area code and new phone numbers would get a new area code. The North American Numbering Plan Administration announced that the new area code will be 539.

There will be no change in local call boundaries, or to 911 or 211 services.

Commission Vice-Chairman Jeff Cloud called an overlay "a cost-effective step."

"An overlay is far less expensive for the phone companies to implement than a split, thus saving customers millions of dollars. Furthermore, the vast majority of area code changes in the United States since 2003 have been overlays," Cloud noted. "Not only does it answer the question of how to treat all within the existing area code equitably, it also puts the area on a footing for the future. Many are already using 10 digit dialing as a matter of routine, and its use is expected to continue to grow. At the same time, businesses and schools with existing operations in various locations of the 918 area code won't have to worry about the trouble and expense of changing their existing numbers."

Commissioner Dana Murphy, who supported the split plan, called the "split versus overlay" a very difficult policy decision.

Commissioners Bob Anthony and Jeff Cloud voted for overlay, Dana Murphy voted against it.

In a news release from the Corporation Commission, there will be no change for telephone customers in the 918 area code until August 7, 2010. At that time, what's known as a "permissive calling" period will begin. Customers will be able to complete a local call within the 918 area code by using 7-digits or 10-digits (area code plus the number).

The news release goes on to say, this seven month "permissive calling" period will give customers a chance to become accustomed to the new calling pattern.

The permissive dialing period will end March 5, 2011.

The new area code numbers will be available beginning April 1, 2011.

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.

The Associated Press contributed to this story.