A fire at the Verizon substation on Church Street in Windsor knocked out telephone service in parts of Isle of Wight, Franklin, Southampton and Suffolk Tuesday morning.

A falling power line likely caused the fire, which is still under investigation. At about 6:50 a.m., a power line fell and came into contact with a Verizon telephone line, according to Dominion Virginia Power spokesman Chuck Penn. He said about 900 Dominion customers lost power as a result, but all power was restored within three hours.

Laura Barnes, a spokeswoman for Verizon, said about 1,600 of the company’s customers lost telephone service. However, service was restored by Tuesday afternoon to most customers, except for sections of southern Isle of Wight and Southampton County.

Rusty Chase, Isle of Wight County’s director of emergency services, said the county’s 911 system is “functional,” but residents in the Windsor and Zuni areas who are without landline service can dial 911 from cell phones or visit their local fire, rescue or police station for assistance.

Chase said Verizon officials told him it could be days before telephone service is restored to parts of the county.