From: craigd@aruba.UUCP (Craig Dunham)
Subject: Re: Token Ring wiring
Date: Mon, 23 Nov 1992 19:22:58 GMT
Organization: Project Zed

In article <BxwA18.3E1@well.sf.ca.us>, shiva@well.sf.ca.us (Kenneth Porter) writes:
|> I've got a couple of PS/2 Model 95's with both Token Ring and
|> Ethernet cards. We use the Ethernet cards for NFS and printer-sharing
|> (the net is shared with Sun's and DOS boxes), but the Token Rings,
|> which were bundled with the PS/2's, are sitting idle. I'd like to try
|> using them for some experiments (I have the NDIS drivers), but I
|> don't know how the cabling works. I'm used to thin-net cabling, where
|> one just runs a hunk of coax between stations and puts a terminator
|> on the ends of the coax.
|> 
|> Each Token Ring card came with a cable with a strange multi-spade
|> connector at the end. How do I connect the two station cables
|> together to make a ring? Do I need some kind of expensive hub box, or
|> can I just fashion an adapter to directly connect the two cables
|> together?

You cannot just plug these two cables together to get a working token
ring network.  IBM's token ring wiring system (and all others, as far
as I know), employs a hub to wire stations on the ring together.
A station can be a PC, an RS/6000 workstation, or any other computer
with a token ring adaptor.  Each station on the network has a cable
which plugs into the hub, so that the network is wired as a physical
star configuration, even though it is an electrical ring.

That is, each station has wire from that station back to the hub, forming
a "star" with the hub in the center.  The hub electrically configures
all the attached stations into a ring, so that the software "token" which
carries information on the network travels from station to station in
sequence, with every station seeing the token before it gets back to
the one which originated it.

In addition, the hub has relays that re-configure the network to maintain
the ring if one of the stations is turned off, has its cable cut, or
otherwise drops out of the ring.  (This doesn't always work, depending on
the nature of the fault).

So, at a minimum, you will need a hub of some sort, such as IBM's 8228 MAU
(Multi-Station Access Unit).  This is basically a dumb unit, but it works
well for small networks.  For larger networks, you may want to look at 3rd
party hubs, such as Star-Tek's.  These "smart" hubs provide some nice
features, such as improved fault tolerance, network statistics gathering,
remote configuration via PC ports, etc..

To wire your PCs to the hub, you can use IBM's wiring scheme, which employs
the multi-spade type connectors and special wiring to plug systems together,
or you can look at 3rd party devices which adapt the output of your token
ring card in each PC to an electrical format which can run across unshielded
twisted pair (UTP) wiring.  This is a MUCH cheaper solution if you already
have your building wired with UTP.  It also allows you to use the same UTP
wiring for running your Ethernet traffic (although not at the same time of
course).

Hope this helps.


-- 
Craig Dunham                     |Internet Style: aruba!craigd@uu2.psi.com
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