SALEM — Oregonians with the 541 area code won’t be forced to change their phone numbers, but their fingers and memories will get a little more work.

That’s the upshot of an Oregon Public Utility Commission decision Tuesday, which will add a second area code — 458 — to the vast region now covered by the 541 area code.

Only phone numbers that are assigned after the new code goes into effect — projected to be in February or March 2010 — will get the new area code, said David Sloan, a state senior telecommunications analyst.

While people with phone numbers today will retain their current ones, everybody in the region will have to adjust to more dialing: They’ll connect using 10 digits, not seven, which means they’ll need to dial and remember longer numbers.

That’s the format used by cell phones.

Already, the rest of the state’s residents have 10-digit dialing on land-based lines, thanks to the adoption of the 971 overlay for the 503 area code in 2000.

Once the 458 code goes into effect, Oregon will have four area codes, each with a capacity of 8 million numbers.

Prior to 1995, Oregon had just one area code: 503. That year, residents in Central and Eastern Oregon had to switch their numbers from 503 to 541 area codes — and had to deal with costs such as reprinting stationery and business cards. That won’t happen this time.

“Typically, the overlay is easier,” said Judy Peppler, the Oregon president of telecommunications giant Qwest, which provides phone service to Bend, Redmond, Prineville and Sisters.

“Customers will get a lot of information before it happens, and then a good six months to get used to it. It will be a nonevent when it cuts over,” she said.

Still, it might seem a strange phenomenon for people who live next door to each other — or even in the same house — to have different area codes.

Phone providers that now serve the 541 region will also need to ensure that switches are properly programmed to guarantee that 458 calls are routed to the correct places, Peppler said.

Twenty-two phone service providers will be affected by the change, the state says.

High demand

Because of soaring demand for cell phones and mobile devices, and also second lines and fax machines, the 541 area code is expected to run out of numbers in 2011, the PUC said. The expanded capacity should be sufficient to handle demand for another 24 years.

An alternate proposal would have carved out a new geographic zone that would have included Albany, Eugene, Roseburg and the central coast.

That proposal would have allowed customers in the affected region to stick with seven-digit dialing — but would have required a phone number change for all customers in one of the two regions.

Sloan told the commission that tourist-based and other businesses fear losing customers if their numbers are changed.

“There doesn’t appear to be a good answer for this, but this plan appears to be the best answer,” Commission Chairman Lee Beyer said.

The commission now has to produce a formal written order, which will begin a 14-month countdown until the 10-digit dialing becomes mandatory. That likely will occur in February 2010, and the new numbers will start being assigned about a month later.

A six-month grace period before the formal switch-over will allow customers to dial local numbers with either seven or 10 digits.

Second choice

The new 458 code comes courtesy of the North American Numbering Plan Administration, which oversees the assignment of area codes. But it wasn’t the first choice.

State officials initially hoped that the 673 code would be available, which would spell out “ORE,” but that code would not work because it is already a dialing prefix in Roseburg, Sloan said.

There will be no cost to phone customers connected with the new area code. It will not affect three-digit numbers, such as 911.