AT&T; to Limit Net Phone Service

AT&T; Corp. said it would suspend Internet phone service for subscribers who fail to keep their location up to date when they move around with the mobile service.

Internet telephone service, known as voice over Internet protocol, can be used anywhere a subscriber has a high-speed Internet connection.

That mobility has prompted concerns by communications regulators who worry that if subscribers do not register their location in the U.S., emergency authorities may not be able to find them when 911 is dialed for help.