Say hello to a new area code — and to dialing 10 digits for a local phone call.

Citing several reasons, the Utah Public Service Commission opted Thursday to bring on the new 385 telephone area code through an "overlay" rather than through a geographic split of the existing 801 area. The new code takes effect next year.

With an overlay, the 385 area code will be assigned to new phone numbers throughout the five-county Wasatch Front region after the 801 code is depleted. One result is that existing customers will keep their phone numbers. Another will be that callers will need to dial 10 digits for local calls.

In announcing the area code plans Thursday, the commission said an overlay is "much less disruptive" for customers and "treats all business and residential customers in Weber, Morgan, Davis and Utah counties the same by allowing them to retain their telephone numbers."

Had the commission opted for the geographic split, only Salt Lake County customers would have retained the 801 area code and their current phone numbers, while those in the four other counties would have switched to 385.

"All customers in the four counties would incur the costs and inconvenience of changing their numbers to the new 385 area code if a split were adopted," the commission said.

The overlay also will avoid confusion, because all long-distance calls will require 11-digit dialing and a split still would have required Salt Lake and Davis county customers to dial 10 digits to call one another. "The use of 10-digit dialing cannot be entirely avoided regardless of whether an area code split or overlay is selected," the commission said in its Thursday order.

The commission noted that several other states have found overlays "easy to implement, and customers have been very satisfied."

"This experience has shown that difficulties with widespread customer confusion with an area code overlay did not materialize as feared," the commission order stated.

The commission also said that technological innovations and telephone device reprogramming have made customers less dependent on dialing numbers to place calls, and the overlay method was supported by the telecommunications industry and the state Division of Public Utilities. The Utah Committee of Consumer Services also advocated the overlay.

The commission sought public written comments on the overlay and split options, and it said Thursday it received "a number" of them, with some favoring an overlay and some favoring a split.

Telecom companies and the division will be required to file periodic reports to the commission on their plans to implement the overlay.