From: robin@pencom.com (Robin D. Wilson)
Newsgroups: comp.sys.next.sysadmin
Subject: Re: 10base-T or thinnet?
Date: 8 Oct 92 14:39:37 GMT
Reply-To: robin@pencom.com
Organization: Pencom Software

In article <root.718320413@merlin> peter@merlin.acadiau.ca (Peter Steele)  
writes:
> What's the true story? NeXT says the ports are autosensing, and
> someone has told us they are not. If someone could clarify this
> we'd appreciate it very much. Thanks.

Well, NeXT is right... We had several machines connected to Thinnet, and just  
removed them from the thinnet, and plugged in the RJ45 on the 10BASE-T;  
rebooted and everything was fine.

I suggest you look at two things:

1)  Your twisted pair.  We have found that FLAT phone wires work OK for  
limited distances, but over long hauls (100+ feet) they seem to have very  
flaky problems.  We recommend that you use twisted copper wiring that meets  
the 10BASE-T spec (x number of twists per foot).

2)  Your ethernet port has died.  We had one go out on us, but both the  
Thinnet and the 10BASE-T died at the same time, so this seems less likely to  
be your problem.

NOTE: for wiring problems it is best to test each piece of the wiring back to  
your HUB.  The easiest way to do this is to test the connection directly at  
the HUB.  Take the machine to the HUB (or the HUB to the machine), plug in  
the wiring that will run from the wall outlet (demarc) to the machine.  After  
you verify that wire, check the wire that runs from the patch panel to the  
HUB.  If both of these work, then it is likely that the wiring from the  
demarc to the patch panel is the culprit.  You could test this by using the  
verified wires on another outlet set.

Of course, I have made a broad assumption here that your wiring looks like  
this:
                            Twisted Pair
------           |      /-------------------\
|NeXT|           |<Wall/                     \         Patch Panel
|    |           |    /                       \      ---------------
------   Demarc\ |   /                         \_____| |x| | | | | |
------__________\+__/                                | ||| | | | | |
------           |                                   ---|-----------
                                                        |
                                                     ---|-----------
                                                     | ||| | | | | |
                                                     | |x| | | | | |
                                                     ---------------
                                                        HUB

If your wiring doesn't look something like this, then you'll need to adjust  
your plan accordingly.  The basic goal is to identify the smallest piece of  
the system that could be broken.  So you break off each segment and test it  
separately.  Good luck.

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