The other day, I noticed that one of my ZyXEL VMG1312-B10A modems’
Johnson graph-plotting function was showing a large burst in errors per unit time during the afternoon of the 7th. Janet had a workman at the house for that time interval although the time he was here was much longer than the duration of the interference period. When I asked her about it she said, "but he wasn’t on the same mains supply!", which is good thinking, and is true, because the site where he was working, an outbuilding, has its own separate mains feed, it isn’t fed from the house. I explained to her the concept of RF interference and had to tell her something about what radio frequency EM energy is, then I think the penny dropped.
Anyway, I have some pretty pictures below, one of "FECs" and one of "CRC errors".
Could someone help me understand how these images were arrived at? I’m being really, really stupid again.
There’s also the question of how/where the PhyR L2ReTX protocol fits in and how it affects the definition of these terms - ie pre- and post- L2ReTX recovery vs protocol ReTX timeout.
FECs:
CRCs:And what kind of tools and what kind of badness in those tools (if any) causes RF interference like this?
Normally the CRC rate is between 0 - 4 per time interval, so very clean. And once again I have forgotten what the unit time interval is in these Johnson graphs; Burakkucat and friends must have reminded me at least twice already - so I will need yet another reminder if you all would be so kind and then I’ll write it down somewhere prominent. Trying a search of the Kitz forum proved too confusing.