10-Digit Dialing Starts in Northeast Tennessee Today

Changes to Local Dialing in the 423 Area Code

Starting on a specific date, residents and businesses within the 423 area code will need to adjust how they make local calls. Instead of using just seven digits, all local calls must now be dialed with 10 digits, including the area code. This change is part of a broader effort to manage the increasing demand for new phone numbers in the region.

The need for this shift comes from the fact that the existing 423 area code was expected to run out of available numbers by the third quarter of this year. To address this issue, a new area code, 729, has been introduced. This means that both the 423 and 729 area codes will coexist in the same geographic area. However, current phone numbers with the 423 area code will remain unchanged. New numbers with the 729 area code will begin being issued starting September 5.

Key Facts About the Change

There are several important details to keep in mind as this change takes effect:

• Current telephone numbers will not change. Residents will still have their existing numbers, but they will now include the area code when dialed.
• All local calls must be made using 10 digits, including the area code. This includes calls within the same area code.
• Long-distance calls will continue to require dialing 1 followed by the area code and phone number.
• Local call definitions will remain the same. What was considered a local call before will still be classified as such.
• Rates and services will not be affected by this change. The cost of calls, coverage areas, and other services will stay the same.
• Emergency numbers like 911 and 988 can still be reached by dialing just three digits. Other special numbers such as 211, 311, 411, 511, 611, 711, and 811 will also remain accessible with three-digit dialing where applicable.

Preparing for the Transition

To ensure a smooth transition, the Tennessee Public Utility Commission recommends taking the following steps:

• Update contact information: Make sure to use your full 10-digit phone number when sharing it with others. This includes friends, family, business partners, and customers.
• Reprogram devices: Any systems or equipment that rely on 7-digit dialing must be updated to accommodate 10-digit numbers. This includes life-safety systems, medical monitoring devices, alarm and security systems, cordless and mobile phones, fax machines, internet dial-up numbers, ankle monitors, speed dialers, call forwarding settings, and voicemail services. If you're unsure whether your equipment needs reprogramming, contact the provider for assistance. All necessary updates should be completed by August 5, 2025.
• Update materials: Ensure that websites, stationery, checks, advertising, and personal or pet ID tags reflect the new 10-digit format with the area code included.

Impact Beyond Chattanooga

This change applies to all areas covered by the 423 area code, including regions around Chattanooga. Residents and businesses in these areas should take the necessary steps to adapt to the new dialing requirements.

By making these adjustments, individuals and organizations can avoid disruptions in communication and ensure that all calls are completed successfully. The goal of this change is to support continued growth and accessibility in the telecommunications sector while maintaining the reliability of local and long-distance services.