This read-only gauge counts TDM Failure events (FC-TDM), where a failure event begins when Loss Of Pseudowire Signal (LOPS) is declared and ends when it clears, with an event counted only in the interval it began in. An admin monitors it to see how many discrete outage events, rather than just cumulative error seconds, the pseudowire has experienced. For example, two brief LOPS events in one interval would increment this counter to 2, even if the two events together lasted only a few seconds total.