The 405 area code covering central Oklahoma might have a companion area code earlier than forecast after an unexpected surge in telephone number requests last year.
The North American Numbering Plan Administration's latest forecast shows numbers could be exhausted in the 405 area code by 2016, four years earlier than its forecast from April 2012.
Oklahoma has four area codes, with 405 serving central Oklahoma and 580 covering western and southern Oklahoma. The Tulsa area and most of eastern Oklahoma are served by 918 and 539, a new overlay area code added in 2011. Customers in 918 and 539 have to dial 10 digits for local calls.
The forecast is important because relief planning for new area codes should begin 36 months before an expected date of exhaustion, said Joe Cocke, a senior relief planner with the North American Number Plan Administration. The group works with regulators and telecom companies to assign area codes and prefixes.
Cocke said a new forecast should be out by the end of April. Recent indicators show number demand slowing in the 405 area code, so the forecast could be pushed back to a later date.
“As we've been watching this area code, the demand has dropped off since September,” Cocke said. “We're monitoring it. We've got a unit that's analyzing all the forecasted data that's coming in from service providers on what they project their needs are going to be.”
Cocke said there are about 800 usable three-digit prefixes for each area code. Prefixes beginning with a one or zero aren't used, and some prefixes are for testing purposes. Others, such as 555-, are partly reserved for fictitious use in television or film.
Just 117 prefixes remain for the 405 area code, less than 15 percent of the available three-digit prefixes, he said.
Regulatory officials said the spike in demand for telephone numbers in the 405 area code could be traced to an influx of new customers in the federal Lifeline program, which provides subsidized landline or wireless service to low-income households. Money for the program comes from Universal Service Fund fees tacked on to most telephone customer bills.
Public utility division officials at the Oklahoma Corporation Commission this month filed cases against five phone companies providing wireless Lifeline service in Oklahoma. Officials want to know if the companies have been verifying applicant eligibility for the program. Phone company reimbursements from the federal Lifeline program in Oklahoma jumped to $218 million last year, up from $90 million in 2011.
Kim Hart, a spokeswoman with Neustar Inc., the contractor that operates the number plan administration, said Lifeline may be a factor in the recent increase in demand for numbers in the 405 area code.
“There are a lot of contributing factors, including if new carriers enter the market, sudden regional growth or the adoption of new technologies,” Hart said. “There's a lot of different things. Increased Lifeline demand could be one of these factors, but we don't know that, because when the carriers request additional number resources from us, their applications don't include the purpose for the numbers.”
Regulators have two options if an existing area code reaches exhaustion. They can split the geographical area or add a new area code on top of the existing one. Cocke said the trend in recent years has been to overlay a new area code.
“The old-fashioned way was a geographical split like we did with the 580, and that reduces the size of the area code,” Cocke said. “We haven't had any area code splits since 2007. All the area codes we've been implementing since 2007 have been overlays.”
The trade-off for an overlay is 10-digit dialing for local calls, he said. But that's often preferable to the business expense of updating office supplies and advertising signs to reflect a new area code.
Oklahoma's original area code, 405, was split in 1953 to create the 918 area code for northeastern Oklahoma. The 405 split again in 1997 to create the 580 for western and southern Oklahoma.