This counter counts seconds during which the T1 path was formally considered unavailable, entered after ten consecutive severely errored seconds per standard path PM rules. Because UASP only increments after that ten-second run, it is the counter an SLA report for this specific T1 circuit should cite for outage time, rather than SESP or ESP which will always show more affected seconds than the path was actually 'down.' For example, a burst of 12 consecutive severely errored seconds would register as roughly 12 seconds of UASP once the threshold is crossed -- the number that belongs on a customer's availability report for that circuit.