In the early 1990s, Bell Atlantic thought there were enough available phone numbers in Maryland to last into the next century. But an explosion in the telecommunications industry - with devices like cellular phones, faxes and modems being used every day by many people - started to gobble up those numbers at a higher-than-anticipated rate, Arnette said.
In response, Maryland will be the first state in the nation to switch to 10-digit dialing as part of a plan that will "overlay" two new area codes to the existing 301 and 410 codes.
Locally, the 240 area code will make its debut early next year, after which houses on the same block could have different area codes.
The alternative to an overlay would have been splitting the state into four geographic regions, each with its own area code. But Bell Atlantic, with the approval of state regulators, decided on the overlay because it won't force people to change their existing numbers, Arnette said.
She said that for some businesses, changing an area code could mean extensive alterations to signs, stationery and other company promotions.
"If you have to change all that to accommodate a new number, it can be costly," Arnette said.
She said that splitting the state again - as was done in 1992 when the 410 area code went into use - would result in enough new numbers to last for seven years, but the overlay will result in enough for 11 years.
Tuesday's news conference was part of a $300,000 statewide campaign that Bell Atlantic began a year ago to educate customers about the change. The campaign included newspaper advertisements, billboards and even coloring books for children.
"I think people know this is coming, so I don't think this will be a surprise to anyone," Arnette said.
Still, the company has heard complaints from customers upset that they will have to dial 10 digits to call their next-door neighbors.
Arnette said she's hopeful that people will understand the long-term benefits of making the change, but she's not about to predict what customer reaction will be Thursday morning.
"We're hoping for the best," she said.