henry@utzoo.uucp (Henry Spencer) (09/16/88)
This is probably of more general applicability... We recently had a nasty problem with an Interlan NI1010A Ethernet interface: lots and lots of collisions, to the point where packet transmission was seriously hampered. This (Unibus) controller brings the signals off the board using a flat cable that is easy to run out through a card cage; the flat cable ends in a little panel with a normal transceiver-cable connector. We'd tacked that panel up on the back of one of our racks. I'd noticed earlier that the #@#$%$%@# clips were not holding the cable onto the connector quite as tightly as they could, and in particular the connector was a bit farther out from the panel at the top than at the bottom, due to the weight of the cable pulling on it. Just on a hunch, I walked back and pressed the connector firmly in. Suddenly the console chatter ceased. Presto, no more collisions. Needless to say, there is now a nice tight cable tie holding that connector firmly against the panel. Note that the contact was not bad enough to actually make transmission impossible! This was what had me fooled for the longest time; I knew from our Suns that the stupid clips didn't always hold snugly enough to maintain contact, but I had sort of thought that contact was boolean: either yes or no. Silly me... -- NASA is into artificial | Henry Spencer at U of Toronto Zoology stupidity. - Jerry Pournelle | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
das@eplunix.UUCP (David Steffens) (09/22/88)
In article <1988Sep15.191100.17488@utzoo.uucp>, henry@utzoo.uucp (Henry Spencer) writes about Ethernet cable clips: > ... I knew from our Suns that the clips didn't always hold snugly enough > to maintain contact, but I had sort of thought that contact was boolean: > either yes or no. Silly me... You betcha... Some years ago when I was still new to networks I had a failure where just a receive pin was disconnected! Packets were transmitted ok but _none_ were ever received. -- {harvard,mit-eddie,think}!eplunix!das David Allan Steffens 243 Charles St., Boston, MA 02114 Eaton-Peabody Laboratory (617) 573-3748 Mass. Eye & Ear Infirmary