Beginning Feb. 28, 2015, all phone calls in the 615 area code will require 10-digit dialing, according to the Tennessee Regulatory Agency.

The change comes a month ahead of an added 629 area code overlay, which will be put in place on March 28, 2015 as all of the numbers from area code 615 are depleted.

The 629 overlay will be the first for Tennessee's six area codes. With the proliferation of mobile phones, computers, readers and security systems using dedicated numbers, area codes across the country have been running out of capacity. There are currently more than 70 area code overlays either in place, pending or planned in North America and the Caribbean.

From the TRA:

What will remain the same?

â¢ Your telephone number, including current area code, will not change.

â¢ The price of a call, coverage area, or other rates and services will not change due to the overlay.

â¢ What is a local call now will remain a local call regardless of the number of digits dialed.

â¢ You will continue to dial 1 + area code + telephone number for all long distance calls.

â¢ You can still dial just three digits to reach 911.

â¢ If 211, 311, 411, 511, 611, 711 or 811 are currently available in your community you will still dial these codes with just three digits.