This PerfCounter64 counter reports a count of Line Errored Seconds, incremented whenever a False Carrier or Errored Symbol event happens within a 1-second poll; the MIB flags this object as deprecated, in the upstream (subscriber-to-network) direction, tallied over the most recent completed bin. An admin uses it as a reliability metric distinct from raw error counts, since it reflects how many whole seconds were affected rather than how many individual errors occurred. 51 seconds logged in cmEthernetAccPortHistoryLES for access port 39 in one interval, concentrated in a short burst rather than spread evenly, points an operator toward a single transient event (like a brief optical glitch) rather than steadily degrading hardware.