The days of seven-digit telephone numbers are fading fast, and come Sunday, you can start practicing life in a 10-digit world.

By Bill Kettler

For the Tidings

The days of seven-digit telephone numbers are fading fast, and come Sunday, you can start practicing life in a 10-digit world.

Oregon gets its fourth area code — 458 — on Feb. 10, 2010, and it will be overlaid on the existing 541 area code. That means we'll all have to dial 10 digits, even for local calls, but we'll have about seven months to practice before the change becomes mandatory.

Telephone companies call this transitional phase the "permissive-dialing" period. Local calls still can be made using seven digits, but as of Sunday, if you dial 541 along with the local number, the call will go through.

"It's not a big thing," said Bob Valdez, public affairs specialist for the Oregon Public Utility Commission. "It's a way for 'early adapters' to start."

The reason for the additional area codes, of course, is the profusion of pagers, cell phones, fax machines and other communication devices that use phone lines.

Researchers for the Public Utility Commission determined the 541 area code could have run out of numbers as soon as 2011.

The overlay allows existing businesses to avoid the costs associated with changing area codes, and helps them maintain contact with customers who might not be aware of the area code change.

Valdez said the transition also gives businesses plenty of time to make sure their phone systems are capable of completing calls to the new area code.

Some business phone systems will have to be reprogrammed to recognize 458, Valdez said.

Cell-phone users won't notice much difference. Nearly all wireless phones already require 10-digit dialing. In Oregon, about 18 percent of all households and adults have only wireless phones, according to surveys conducted by the National Center for Health Statistics, a division of the federal Centers for Disease Control and Prevention.

The overlay is new here, but it's old hat in other areas. Portland got its second area code (971) in 2000, and northwestern Oregon was added to the 503/971 overlay in 2008. Larger metropolitan areas have several area codes.

Phone rates won't be affected by the dialing change. Calls that formerly were billed as local still will be local calls even though the area code will have to be dialed. Calls that were formerly long distance still will be long distance.

Valdez said the telephone network switches know which calls are local and which are long distance. If someone forgets to dial a 1 for a long-distance call in the same area code, the switch won't allow the call to go through and there will be a message saying it's necessary to dial 1 to complete the call. If someone adds an unnecessary 1 to a local number, the call won't go through and there will be a message saying it's not necessary to dial 1 to complete the call.

"Those switches are pretty darn smart," he said.

Dialing 9-1-1 for emergencies will not change.

Reach reporter Bill Kettler at 776-4492 or e-mail bkettler@mailtribune.com.