HARRISBURG — Ten-digit dialing will be required inside the 814 area code starting April 3.

Because a second area code is being overlaid, callers will have to dial the area code for each call. Callers can begin using 10-digit dialing for all telephone calls.

Beginning in May, newly activated phone numbers may have a 582 area code, the state Public Utility Commission said.

The 814 area code covers all or parts of 27 counties across central and northwestern Pennsylvania,including Blair and surrounding counties.

The 582 area code will be assigned to new telephone numbers once the available supply of numbers in the current 814 area code is exhausted.

Starting April 3, anyone attempting to make a call in the 814 area code using only seven digits will receive a recorded message prompting them to hang up and redial the call using the full 10-digit number.

Consumers and businesses are encouraged to check devices that store telephone numbers — including cellphones and other devices with “speed dial” functions — to be certain that all the stored contacts include the area code. Any new contacts should include the area code.

It is essential to double-check devices like medical alert systems, alarms and any other systems that automatically make calls, to be certain they are set up for 10-digit dialing, the PUC said.