From: medici@dorm.rutgers.edu (Mark Medici)
Newsgroups: comp.dcom.lans.ethernet
Subject: Re: Can Token Ring wire be used for 10BaseT?
Date: 10 Sep 92 19:24:14 GMT
Organization: Rutgers Univ., New Brunswick, N.J.

nolan@tssi.com (Michael Nolan) writes:
| perl@dwrsun4.UUCP (Robert Perlberg) writes:
|
| >Our building is wired for token ring.

[ ... standard Token-Ring over STP wiring description deleted ... ]

| >My question is, can this wiring be used for Twisted Pair Ethernet?

Yes, and no.  Read on.

|  Can
| >I make (or buy) an adapter that will connect an RJ45 to a token ring
| >connector and use the existing building wiring for 10BaseT?  (With, of
| >course, appropriate 10BaseT transceivers in the offices and 10BaseT
| >hubs in the communications room.)

You could make the adapters (probably even buy them) to hook 10Base-T
into the IBM data connectors.  You may even be able to get away with
running 10Base-T over these wires.  However, the IBM Type-1 cable is
not compatible to the 10Base-T spec.  My guess is that this might work
for short distances, but I wouldn't want to gamble my data or money on
it.


| I think it must be possible, because my son is in Donner hall at Carnegie-Mellon
| and the building apparently was originally wired for token ring but later
| converted to 10Base-T.  They sell a token-ring-to-10Base-T cable for
| around $30 which plugs into the IBM Token Ring jack in the dorm room,
| has some kind of balun or transformer on it, and an RJ45 cable which goes
| into the RJ45 jack on the 10Base-T NIC.  (I saw LatticeNet equipment in the 
| wiring closet in the basement, if that means anything.)
 
There's the key: LatticeNet.  LatticeNet is a pre-10Base-T network
topology that uses STP cabling.  While LaticeNet is not 10Base-T, it
does allow standard Ethernet packets to be transmitted via IBM Type-1
STP wiring.  On the workstation/server end, you would need either a
LatticeNet network interface card, or the adapter cable described
above.

However, you do need to realize that LatticeNet, though it does use
Ethernet protocols, is proprietary at the lower network layers.  I've
never purchased their equipment, but would guess that the specialized
marketing niche would make them expensive.  Also, if you decide to use
LatticeNet, you will have to maintain your STP cable plant, and new
expansion would also require more STP and LatticeNet if you want to
stay homogenous.  These factors may cause your long-term costs of
using the existing STP to exceed the extra short-term costs of pulling
new UTP.

So, to summarize:

 You CAN run Ethernet over IBM Type-1 STP cable, using LatticeNet.

 You MAY be able to run 10Base-T Ethernet over STP, but this would
 be out of spec and the results cannot be predicted in advance
 (perhaps someone on this list has tried it).

 You SHOULD compare the costs of the LatticeNet adapters, hubs,
 and on-going maintenance of the STP cable plant with the costs
 of pulling level-4 or level-5 UTP and using standard 10Base-T
 components.  You may find that the best use of your STP will be
 to use them as pull-strings for level-4 UTP.
-- 
_________________________________________________________________________
RUCS     | Mark A. Medici, Systems Programmer III, User Services Division
User     | Rutgers University Computing Services, New Brunswick, NJ 08903
Services | [medici@gandalf.rutgers.edu]                    [908-932-2412]
Newsgroups: comp.dcom.lans.ethernet