A device is disclosed for continuously cutting a fiber cable into sections, as well as a process for operating this device. The device includes a rotary knife carrier fitted with a plurality of knife blades, against which the fiber cable is pressed via a compression wheel. Wear and break of the knife blades are sensed by one or more structure-borne noise sensors. In addition, a characteristic parameter is formed from the signal from the structure-borne noise sensor(s) and compared with a comparison value. Deviations from the comparison value are recognized as disturbances.