This Counter32 tallies Far-End Protection-Line Failure conditions, declared specifically when this device receives a Signal Failure indication in the K1 byte concerning the protection line itself, meaning the far end has reported its protection line -- the backup path -- has failed. A rising count here is particularly significant because it means that even if the working line is fine right now, this protection group effectively has no working fallback if the working line were to also fail, since the backup path itself is reporting trouble. For example, an admin seeing this counter increment should treat it with urgency even without an active working-line fault, since it indicates a currently-unavailable safety net for this protected circuit.