This counter accumulates the number of severely errored seconds (SES) that the far-end equipment is detecting during the current 15-minute period, using the same 30% error threshold definition as the local SES counter. Seeing high far-end SES while local SES is low indicates the problem is on the path from your end to the remote end, while the opposite suggests the return path is degraded. This metric is essential for determining which side of the line needs attention from your carrier or equipment vendor.