This counts errored blocks -- E1 frames in which at least one bit was corrupted -- detected on this E1 port. EB is the broadest block-error counter in this table, since SES and most BBE events are drawn from it, so a rising EB count on this port, even before SES climbs, is the earliest sign of block-level corruption worth checking -- and this specific object covers a closed 24-hour history bin -- a final, day-over-day comparable count rather than a live figure. For example, over that completed 24-hour bin, this E1 port might show this counter at 400 -- a concrete count the admin can trend against neighboring bins to judge whether the condition it reflects is worsening.