Starting this fall, El Pasoans and other residents of the 915 area code will have to dial a 10-digit number — rather than seven digits — to make local calls.

The change is needed to accommodate 988 as the three-digit National Suicide Prevention Lifeline starting in July 2022. The 915 area code is among several in Texas that have phone numbers with a 988 prefix that would complicate the implementation plan if 10-digit local calls weren’t required.

Mandatory 10-digit local dialing in the 915 area code begins Oct. 24. A six-month transition period begins on April 24, according to the Public Utility Commission of Texas.

Seven-digit local calls will still work during the transition period, but phone users are encouraged to begin using 10-digit local dialing.

Some older safety and security equipment — such as medical alert devices, and alarm and security systems — may need to be programmed to use 10-digit dialing.

If you have seven-digit local numbers in your mobile phone contact list, you’ll need to add the area code by October.

Other Texas area codes affected by the change include 254, 361, 409, 806, 830 and 940.