This read-only PerfTotalCount reports the count of frames truncated because the DSL receiver overran and had to cut a frame short, scoped to one specific 15-minute bucket out of the 96 stored for that DSL port. Operationally, truncated frames are lost data, and a rising count suggests the receiver is being overwhelmed faster than it can process incoming bits. For example, if bucket 20 alone shows truncated frames while the rest of the day's buckets are clean, the admin can correlate that 15-minute window with a logged event like a card reset.