At least 12,000 customers in the District, Maryland and Virginia lost telephone service during Hurricane Isabel.
That figure is expected to increase as people who were told to evacuate their homes begin to return and find their phone service out.
“I think that number will grow,” Verizon Communications spokesman Mark Marchand said.
Verizon has an estimated 30 million customers in 29 states and the District and is the leading provider of local-calling service in the Mid-Atlantic region.
About 6,300 customers in the District and its suburbs reported loss of phone service. That is three to four times the number of reports of problems on a typical day.
About 5,700 customers in the Hampton Roads area reported loss of service. That is seven to eight times the number of complaints on a typical day.
Verizon workers yesterday continued to replace an estimated 500 telephone poles destroyed in Maryland and Virginia.
The phone company’s repair crews worked in tandem with crews restoring electricity service, Mr. Marchand said.
About 158 of Verizon’s call-switching centers were still operating with a backup power source yesterday because electricity was cut off when the hurricane snapped power lines. That allowed the company to continue connecting phone calls and routing Internet traffic over its telecommunications network.
Loss of service for telephone customers led to some increases in the number of cell-phone calls.
Verizon Wireless, which has 34.6 million subscribers, saw an increase in call volume of about 25 percent beginning Friday, spokesman John Johnson said.
AT&T Wireless spokesman Ritch Blasi said his company’s 21.5 million subscribers didn’t make significantly more calls during the storm.
Like the call-switching centers, cell sites operated by wireless companies also had to rely on backup power sources, including batteries and diesel generators, the companies said, but service wasn’t interrupted.
While Hurricane Isabel had only a modest effect on telecommunications service by snapping some telephone lines, it did expose one weakness: Cordless phones failed to work once the storm cut power lines.
Cordless phones plug into outlets.
Standard telephones get their power through the plug that connects them to a consumer’s phone provider. Even if an electric company’s power supply to a home is cut, power will surge through the connection to standard telephones as long as the telephone line isn’t severed.
But cordless phones go dead.
Nearly 3 million homes and businesses lost power in the District, Maryland and Virginia owing to the hurricane.
“We try to remind people that when they buy a cordless phone, it won’t work if the power is out,” Mr. Marchand said.