SAN ANGELO, Texas (AP) _ Panicked San Angelo residents who awoke to a 30-minute Civil Defense warning on their television sets jammed emergency phone lines to find out whether to ignore it or take cover under their beds.

The false alert appeared on all cable television stations at 6:28 a.m. Wednesday and continued until 7:04 a.m., officials said.

Not only residents but off-duty firefighters called in to find out if the alarm was real, said Fire Department Battalion Chief Dwight Clark.''Quite a few didn't know whether to go to work or get under the bed. One guy that called got real upset. He was missing his cartoons.''

The false alert was triggered when water from overnight rains migrated into an underground telephone cable, officials said.

''We just tried to explain as quickly as we could that it was only a malfunction,'' Clark said of the more than 100 calls fielded during the half hour.Fire department personnel could not stop the alert because the department's control system had not activitated it, he said.

The cable line was repaired later in the day, said Melissa Horinek, a General Telephone Co. spokeswoman.

Rogers Cablesystems general manager Don Dooley said that the television offices were closed when the alert came on the air.

''We're working together to make sure this never happens again,'' Dooley said. ''If we don't come up with a satisfactory solution, there's a possibility we will have to come up with another system.''