Telephone service was cut Thursday morning to the main lines of all Lawrence schools and district headquarters.
Service was restored about 3:30 p.m., said AT&T spokeswoman Chelsey Ilten.
She said a construction crew at Third and Wisconsin streets cut a marked cable line. Tim Cast, a city concrete supervisor, said a crew was installing a valley gutter at the intersection.
No calls could be received on district phones, but outgoing calls could be made.
Callers to the district after the line was cut heard a busy signal. The district set up its hot-line cell phone - (785) 218-4970 - that administrators answered. Any school or district official could be reached through that number.
The school district's emergency notification system, SchoolMessenger, was not affected because it is activated via a Web site or cell phone, said Julie Boyle, a district spokeswoman.
Administrators decided to use local media and other nonemergency methods of notifying parents and other members of the public about the outage - instead of employing the emergency system. Administrators want to use the messaging system for emergencies only, Boyle said, and they were unsure how long the phone problem would persist.