Path: utzoo!attcan!uunet!aplcen!uakari.primate.wisc.edu!zaphod.mps.ohio-state.edu!mips!bridge2!mbt From: mbt@bridge2.ESD.3Com.COM (Brad Turner) Newsgroups: comp.dcom.lans Subject: Re: Cost of 10BaseT Summary: clarification of 3Com Pairtamer Message-ID: <1387@bridge2.ESD.3Com.COM> Date: 5 Mar 90 17:51:57 GMT References: <1990Feb26.082610.7963@hellgate.utah.edu> <27543@cup.portal.com> Organization: 3Com Corp., Mt. View, CA Lines: 71 John_Robert_Breeden@cup.portal.com writes: >>>1) If I go the 10BaseT route, what are the pieces of hardware I need to >>>buy, and what are the costs? I realize I need 5 10BaseT cards and the >>>RJ45. What else? >> >>First, you need the chassis that the 10BaseT cards go into. 3Com has a >>box that the call a MultiConnect repeater. I have one here. It holds >>about 15 cards, I think (you don't really expect me to walk to the other >>end of the building to verify that, do you?) 3Com also has a device that >>they call a PairTamer. It converts thinnet to 10BaseT. If you use a thinnet >>card in the MultiConnect box, then you need a pair of PairTamers for each >>TP wire. I hear that 3Com will soon have a card for the MultiConnect that >DANGER WILL ROBENSON, DANGER!!! The 3Com pairtamer IS NOT A 10BASET DEVICE!!! >it is a BALUN - A PASSIVE DEVICE, if you bother to read the 10baseT draft, [stuff deleted] >If the idea of using baluns and daisy-chaining nodes with TP is is matching >"what 3Com has been selling as 10BaseT" - that's just, well WRONG. [stuff deleted] >So the bottom line is if you use the solution above, you are NOT 10baseT >but instead are running a PROPRIATARY 3COM SOLUTION - nothing wrong with >that as long as you are prepared to live with the fact that you may (read >most likely) will not be able to use other vendor's true 10baseT product >in the same network. The Pairtamer has NEVER been marketed as a 10BaseT product! It is marketed as a 10Base2 product which is exactly what it is. The Pairtamer can and will coexist with other 10BaseT products. For example the configuration below: --- thinnet XXX repeater that supports 10BaseT and 10Base2 ][ 2 pair of TP wiring = 1 pair of TP wiring @ Pairtamer module ## end node (either a 10BaseT enet interface or a 10BaseT transceiver) -------XXXXXXXX----@===================@----XXXXXXXX------- ][ ][ ][ ][ ][ ][ ][ ][ ][ ][ ][ ][ ][ ][ ][ ][ ][ ][ ][ ][ ][ ][ ][ ][ ][ ][ ][ ][ ][ ][ ## ## ## ## ## ## Where the confusion is going to happen is when folks do not understand the difference between the Pairtamer and 10BaseT devices. You CANNOT plug an RJ-45 into a Pairtamer on one end and a 10BaseT device on the other end (well actually you can, the plugs will fit together, but it is not going to function.) In some instances the Pairtamer does make more sense than 10BaseT (e.g. cost per port, # of pairs required, repeater penalty.) Before this turns into a commercial; call 800-NET-3COM if you want more information. -brad- v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v Brad Turner |2081 Shoreline Blvd.|(415) 969-2099 ext 217 | I speak for myself 3Com Corp. |Mtn. View, CA 94043 |mbt@bridge2.ESD.3Com.Com| NOT for my employer -- v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v Brad Turner |2081 Shoreline Blvd.|(415) 969-2099 ext 217 | I speak for myself 3Com Corp. |Mtn. View, CA 94043 |mbt@bridge2.ESD.3Com.Com| NOT for my employer