This read-only PerfTotalCount reports the count of frames received with CRC checksum errors on the DSL port, scoped to one specific 15-minute bucket out of the 96 stored for that DSL port. Operationally, CRC errors are a direct measure of line-quality problems, since they indicate data was corrupted somewhere on the copper loop. For example, a spike of CRC errors in one 15-minute bucket, followed by clean buckets afterward, suggests a transient noise event on the copper pair rather than a permanently degraded line.