One of these brave agents chewed through some PBX equipment when I was in college, and that's how we found out that the phone system's failure mode was to emit

One of these brave agents chewed through some PBX equipment when I was in college, and that's how we found out that the phone system's failure mode was to emit a sustained, wraith-like shriek, very similar to the sound we students made as it woke everyone up at 2 AM.