KNOXVILLE, Tenn. (WVLT) - With a new area code coming to East Tennessee in September, 10-digit dialing will be required ...

There is also another type of postal code, the ZIP + 4 code. According to unitedstateszipcodes.org, the ZIP + 4 was established in 1983 and identifies an even more specific location within a ZIP code.

"Area code overlays are really, really common." After Aug. 5, anyone with a 423 area code who tries to place a phone call with only a seven-digit phone number will hear a recording.

People in the 760 area code will be able to use 10-digit dialing for local calls beginning May 2. After Oct. 24, it will become mandatory to dial the full 10-digit number when making local calls.