The North Platte Fire Department responded to a fire alarm shortly after 11 a.m. Tuesday at the Century Link phone company building at Fourth and Vine.
Interim Fire Chief Dennis Thompson said a technician was working on a panel.
There was no damage to the building and no people were in danger, Thompson said.
Century Link Market Development Manager Karl Bieber said a technician tested the alarm system in the building earlier in the day. For an unknown reason, one of the sensors tripped the alarm later Tuesday and the fire department was automatically notified.
The building was formerly home to Qwest, and before that, to Northwestern Bell.
This report was corrected Wednesday morning.