To ensure new telephone numbers are available, the Tennessee Public Utility Commission approved adding the new 729 area code to the geographic region served by the 423 area code. This process is known as an area code overlay.
What is an area code overlay?
An overlay is the addition of another area code (729) to the same geographic region as an existing area code (423). An overlay does not require customers to change their existing area code but does require using a new dialing procedure to complete calls.
Who will be affected?
Anyone with a 423 area code will be affected. The 423 area code covers two non-contiguous regions in eastern Tennessee, serving communities such as Chattanooga, Bristol, Johnson City, and Kingsport, as well as many other smaller communities. The new 729 area code will serve the same geographic region currently served by the existing 423 area code.
What will be the new dialing procedure?
All calls in the 423 area code currently dialed with seven digits will need to be dialed using the area code + 7-digit telephone number. The same dialing procedure will apply to telephone numbers that are assigned in the new 729 area code.
When will the dialing change begin?
Effective August 5, 2024, dial the area code + telephone number whenever you place a call, including calls within your same area code. If you forget and dial just seven digits, your call will still be completed until February 5, 2025.
Beginning February 5, 2025, you must dial the area code + telephone number on all calls, including calls within your same area code. After this date, if you do not dial the area code + telephone number, your call will not be completed. If you dial a number and do not include the area code, a recording will instruct you to hang up and dial again, including the area code.
Beginning March 5, 2025, new telephone lines or services may be assigned numbers with the new 729 area code. If you have a number in the new 729 area code, you must dial the area code + telephone number or the call will not complete.
What needs to change?
- Dial the area code + telephone number for local calls.
- All services, automatic dialing equipment, or other types of equipment that are programmed to dial a 7-digit number will need to be reprogrammed to include the area code. Some examples include life safety systems and medical monitoring devices, fire or burglar alarms, security systems, gates, fax machines, Internet dial-up numbers, speed dialers, call forwarding settings, voicemail services, and similar functions.
- Update your websites, personal and business stationery and checks, advertising materials, personal and pet ID tags, and other such items to ensure the area code is included.
What remains the same?
- Your telephone number, including your current area code.
- The price of a call, coverage area, or other rates and services will not change due to the overlay.
- What is a local call now will remain a local call regardless of the number of digits dialed.
- You can still dial just three digits to reach 911 and 988, as well as 211, 311, 411, 511, 611, 711 or 811 if available in your area.
Who may you contact with questions?
You may visit the Tennessee Public Utility Commission website at www.tn.gov/tpuc
