What is Ten-Digit Dialing?
A ten-digit dialed telephone call requires entering both the three-digit area code and the seven-digit telephone number to complete the call, even if the area code is the same area code as your own. When an area code transitions to ten-digit dialing, you will no longer be able to dial seven digits to make a local call.
Transitioning to ten-digit dialing will not affect your current telephone number. Your phone number, including your area code, will not change. In California and in Illinois area code 708, you may be required to dial the number "1" before the area code and seven-digit phone number for local calls.
Upcoming Transitions to Ten-Digit Dialing: Where and When?
There are 82 area codes in 35 states and one U.S. territory that currently use "988" as their local exchange and allow seven-digit dialing. A local exchange, also known as a central office code, is the first three numbers of a seven-digit telephone number. To prepare for implementation of a quick way to dial the National Suicide Prevention Lifeline – using only "988" to connect callers to the Lifeline – these area codes must transition to ten-digit dialing for all calls, including local calls.
The North American Numbering Plan Administrator has a list of the states and area codes that will be affected. You can check the list to find out if your area code is one that will be transitioning: https://nationalnanpa.com/transition_to_10_digit_dialing_for_988/docs/NPAsRequiredtoTransitionto10DD.pdf
If you have one of these area codes, beginning on October 24, 2021, you must dial ten digits (area code + telephone number) for all local calls. On and after this date, local calls dialed with only seven digits may not connect, and a recording will inform you that your call cannot be completed as dialed. You must hang up and dial again using the area code and the seven-digit number.
Ten-digit dialing for local calls has been enabled in these area codes since April 24, 2021, and you can begin dialing ten digits anytime, though seven-digit local calls will still be completed prior to October 24, 2021.
Unrelated to the upcoming "988" transition, the "202" area code moved to ten-digit dialing on October 9, 2021. Calls dialed using only seven digits will no longer be completed. This move will allow for a new area code, "771," to be added to the current "202" area.
What Changes Will Businesses Need to Make?
If your company uses a PBX or VoIP phone system, you may need to update or reprogram it for ten-digit dialing. Because ten-digit dialing became available in April 2021 in the areas where seven-digit dialing will be phased out in October 2021, reprogramming of PBX or VoIP systems can begin at any time. You should plan to complete any needed reprogramming and test your system before October 24, 2021.
Why Is Ten-Digit Dialing Necessary?
There are more phones in America than there are people, and each phone needs its own phone number. Beginning in the early 1990s, to accommodate the growing need for more phone numbers, some areas began to add a second area code for local calls. Dialing both the area code and the seven-digit number was necessary to ensure the call reached the intended recipient. As more area codes begin to run out of new seven-digit numbers to assign, a second local area code may be added, requiring that area to transition to ten-digit dialing.
In 2020, the FCC established "988" as the new, nationwide three-digit phone number for the National Suicide Prevention Lifeline. The new three-digit dialing code will be available nationwide by July 16, 2022 and will provide an easy to remember and easy to dial three-digit number to reach suicide prevention and mental health counselors, similar to "911" for emergencies and "311" for local government services. To help facilitate the creation of "988", area codes that use "988" as a local exchange, or the first three digits of a seven-digit phone number, will need to use 10-digit dialing.
Ten-Digit Dialing (pdf)