Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!bionet!apple!motcsd!hpda!hpcupt1!hprnd!pat
From: pat@hprnd.HP.COM (Pat Thaler)
Newsgroups: comp.dcom.lans
Subject: Re: How to Break your Cheapernet - bad Tee pieces
Message-ID: <2230015@hprnd.HP.COM>
Date: 17 Jul 89 17:12:35 GMT
References: <335@wcc.oz>
Organization: HP Roseville Networks Division
Lines: 24

Glen Marianko writes:
 
> Just to echo a bit, several months back someone mentioned a bad
> T causing problems on his net.  Wiseguy that I am, I thought how
> could you possibly have a bad T?  Well, living through one does
> open up one's eyes!
> 
> This is a VERY serious problem.  I suspect that if one uses BNCs
> and Ts from the same manufacturer, they stand a better chance of
> interoperating better.  I can't confirm this, however.
> I don't know if there is a BNC "standard" that describes the OD of
> the center pin, but one can visually see that it does vary between
> manufacturers.
>
To quote from the 10BASE2 "cheapernet" standard:
  "High-quality versions of these connectors (per IEC 169-9) are
   recommended in order to meet dc loop resistance and reliability
   considerations."
In addition to the IEC spec, there is a Mil spec, but I don't know 
the number off-hand.  These specs cover dimensions.  I think they 
also cover plating type and thickness.  Improperly installing 
connectors on the cable can also lead to problems.

Pat Thaler