NANPA Planning Letter (PL) Number 403 - Oklahoma - NPA 539 to Overlay NPA 918

The Oklahoma Corporation Commission approved an all services overlay as the relief method for the 918 NPA area on 1/4/10. The new 539 NPA will serve the same eastern portion of the state currently covered by the 918 NPA (including communities such Bartlesville, Clayton, Cushing, Fairfax, McAlester, Miami, Muskogee, Okemah, Poteau, Sallisaw, Tahlequah and Tulsa). The overlay timeline was identified as:

• 08/07/10 – Start of Permissive 10-Digit Dialing
• 10/01/10 – Earliest Date to Order Central Office Codes in New 539 NPA
• 03/05/11 – End of Permissive Dialing and Start of Mandatory 10-Digit Dialing
• 04/01/11 – Earliest New NPA Central Office Code Activation date; and, Effective Date of the New 539 NPA

Although subscribers may use either seven- or 10-digit dialing for local calls within the overlay area during the permissive dialing period, 10-digit dialing is encouraged. Additionally, when preparing for overlay area code relief, carriers are strongly encouraged to prepare their switches to begin sending 10-digits prior to the mandatory 10-digit dialing conversion date for customers.

The dialing for both 918 and 539 NPAs will be as follows:
~ Local Home NPA (HNPA) or Foreign NPA (FNPA) Call … 10-Digits (NPA-NXX-XXXX)
~ Toll HPNA or FNPA Call … 1+ 10-Digits (1+ NPA-NXX-XXXX)
~ Operator Services HNPA or FNPA Call … 0+ 10-Digits (0+ NPA-NXX-XXXX)

International and domestic carriers should ensure network-wide activation of the new 539 NPA prior to 4/1/11. Verification of proper routing may be tested from 1/4/11 through 5/2/11 by dialing 539-539-1539. For additional information, visit www.nanpa.com.