An electrical mishap knocked out communications at the North Carolina State Highway Patrol's main facility on Blue Ridge Road in Raleigh.
The highway patrol's Voice Interoperability Plan for Emergency Responders, or VIPER, was knocked out around 4:30 p.m. for 30-35 minutes, authorities said.
A worker not associated with the highway patrol was performing maintenance on a communications tower when the incident occurred.
VIPER is an 800 MHz radio system implemented after 9/11 that is used across the country and state.
A communications is fully operational again, authorities said.