803 area code customers need to use the area code in placing local calls starting Saturday, April 25. 
The move to 10-digit calling is due to the new 839 area code that will cover the same area as 803.

The change was ordered by the Public Service Commission to ensure a continuing supply of phone numbers..  

If you fail to dial all 10 digits you will hear a recording telling you to hang up and re-dial. 

Windstream can assign numbers with the 839 area code for new phone service beginning May 26. 
10-digit dialing also will be required for calls using the 839 area code.

Some automatically dialed calls, such as life-safety systems, alarm and security systems and call forwarding settings, may require reprogramming to include the new dialing procedure. 
PBX equipment also may need to be reprogrammed.

The switch will not affect the cost of local phone calls or affect long-distance calls.You need to dial 1 plus the area code and 7-digit number for long-distance calls . 
Emergency calls to 911 will not require the area code.