This read-write Gauge sets how many P-bit Severely Errored Seconds must accumulate in the near-end bucket before the device raises a Threshold Crossing Alert for the circuit; the factory default is 4. An admin lowers it to get earlier warning of DS3 line trouble (a value of 4 means the alert only fires once 4 p-bit severely errored seconds have been counted, since a high density of P-bit parity errors (severely errored framing, or an AIS defect) occurred).