Changes are coming for telephone customers in the 405 area code.

Starting April 24, all local calls within the 405 area code will require 10 digit dialing (area code plus local number).

The move to 10 digit dialing for local 405 area code calls is necessary to enable the addition of another area code for the area currently served by only 405, according to the Oklahoma Corporation Commission.

The additional area code (572) is needed to ensure there will be enough telephone numbers available for the area.

Here is the schedule for local-call 10-digit dialing within the 405 area code and the addition of the 572 area code:

April 24 — Mandatory 10-digit dialing begins.

All local calls will require the area code plus local number.

May 24 — 572 area code added to the area that had been served only by 405.

The addition of the 572 area code will not change existing 405 telephone numbers.

Also, there will be no change in the local call boundaries.

Local calls within the area will remain local calls, regardless of whether the number called has a 405 or 572 area code.

The area currently served by the 405 area code is the second area in Oklahoma to institute 10-digit dialing.

The first was the area served by the 918 area code, which is now served by both the 918 and 539 area codes.

539 was added in 2011, accord ing to the corporation commission.