csDs3Ds1CurrentUASs is a read-only PerfCurrentCount counter reporting the number of Unavailable Seconds — seconds counted once ten consecutive severely errored seconds occur on the DS1 — that this channelized DS1 (T1) circuit carried inside the DS3 has recorded in the current 15-minute measurement interval, i.e. right now. A rising count here is the operational signal that an extended outage of that individual T1 channel is happening on that interface, which is exactly the kind of degradation a monitoring admin wants an early warning of before it causes an outage. For example, an admin polling csDs3Ds1CurrentUASs on this channelized DS1 (T1) circuit carried inside the DS3 every few seconds and watching the count jump upward in real time would immediately suspect an extended outage of that individual T1 channel, and could start a bit-error-rate test before the fault gets worse.