frankh@durin.laguna.sparta.com (Frank Halsema) (04/03/91)
I have read a lot about 10BaseT and I am considering using it in a new facility. Everything I see has the twisted pair connector as a RJ45 but inplications are that twited pair uses two pair or four wires. My question is how many pair do I need and if it is two pair why does 10BaseT use an RJ45 connector. Frank Halsema UUCP: durin!frankh SPARTA, Inc. Internet: frankh@laguna.sparta.com 23041 de la Carlota, Suite 400 Laguna Hills Ca, 92653 (714) 768-8161 EXT 339 (714)583-9114 FAX
woody@ucscb.UCSC.EDU (Bill Woodcock) (04/03/91)
> I have read a lot about 10BaseT and I am > considering using it in a new facility. > Everything I see has the twisted pair connector > as a RJ45 but inplications are that twisted pair > uses two pair or four wires. My question is how > many pair do I need and if it is two pair why > does 10BaseT use an RJ45 connector. 10BASE-T does indeed use four conductors. On an RJ-45 modular jack, pin 1 is Rx+, pin 2 is Rx-, pin 3 is Tx+, and pin 6 is Tx-. When you go to your wiring closet, they are normally punched down in that order as well, pin 1 to row 1, pin 2 to row 2, pin 3 to row 3, and pin 6 to row 4. As to why 10BASE-T uses an RJ-45, I know of a couple of reasons, but I don't know that any of them are "official." First and most important, it's to keep people from plugging their phones into data jacks, and vice versa. Secondly, it's to allow for people in the future plugging their phones into data jacks, but making it work. You'll find that ISDN normally uses pins 4, 5, 7, and 8. -Bill Woodcock BMUG NetAdmin _______________________________________________________________________________ 0000 : 0600 0800 7700 FE00 FF 0 FF8 7F 0 3 00 48 bill.woodcock.iv 0010 : CC00 7C00 0C00 1000 2800 440 8200 40 0020 : C000 4000 8000 C000 C 00 800 80 48 0 9 woody@ucscb.ucsc.edu 0030 : FF00 F000 7F80 CC00 CC 0 7 80 7 80 CC 6 0040 : CC00 7F80 9800 7800 CC00 CC0 CC 0 C 00 2355.virginia.st 0050 : CC00 CC00 FC00 CC00 CC 0 2000 10 0 7 00 C 0 0060 : CC00 CC00 CCC0 4800 2 00 1 00 2 00 48 0 9 berkeley.california 0070 : 4800 2400 1200 1000 2800 4 00 8 00 E0 0080 : 3000 6000 F000 6000 000 60 0 600 C0 0 01C 94709.1315 _______________________________________________________________________________
haas%basset.utah.edu@cs.utah.edu (Walt Haas) (04/03/91)
In article <1991Apr3.153750.19033@jhereg.osa.com> andrew@jhereg.osa.com (Andrew C. Esh) writes: > >If anyone is interested, I can write a longer posting on the ins and outs >of 10baseT, and the experiences I and my co-workers have had with it. I'd be interested. We have started to do 10BASE-T for offices where there is little chance that a second computer will be added. Thinnet still wins for student bullpens and labs with lots of machines in one room. The cost to us is about $300 + wiring per computer for 10BASE-T. Thinnet cost is a little more than half that. The big win with 10BASE-T is the situation where a computer locked in somebody's office goes nuts and starts to hose the network, or where somebody unplugs their cable. With 10BASE-T we don't have to check every office, we just check the hub, and wiring faults are dealt with automatically. In engineering offices where there are likely to be additional computers we still like the hub idea, but set up a multiport thinnet repeater and assign a port to an office. This gives us the same automatic recovery from wiring faults, at a slightly greater cost per office than 10BASE-T, with the chance to inexpensively add up to 14 more computers per office. -- Walt Haas haas@ski.utah.edu
andrew@jhereg.osa.com (Andrew C. Esh) (04/03/91)
In article <5438@durin.sparta.COM> frankh@durin.laguna.sparta.com (Frank Halsema) writes: >I have read a lot about 10BaseT and I am considering using it in a new >facility. Everything I see has the twisted pair connector as a RJ45 but >inplications are that twited pair uses two pair or four wires. My >question is how many pair do I need and if it is two pair why does >10BaseT use an RJ45 connector. > > >Frank Halsema UUCP: durin!frankh >SPARTA, Inc. Internet: frankh@laguna.sparta.com >23041 de la Carlota, Suite 400 >Laguna Hills Ca, 92653 (714) 768-8161 EXT 339 (714)583-9114 FAX 10baseT tends to be used in the same "wiring closets" (IDF's) as telephone equipment, as well as the same wall plates, so I would guess the use of RJ45 is an attempt to make use of existing telephone wiring, without getting it confused with RJ11. RJ11 won't work with 10baseT jacks or transceivers, since the pairs are 1-2, and 3-6, with the lines as T+, T-, R+, and R-, respectively. Six wire RJ45 doesn't work, since you need pin 1 on the 8 wire RJ45. Pin 1 on the six conductor version connects to pin 2 of the 8 wire outlet. You have to use an 8 conductor RJ45 to plug into the 10baseT outlets and transceivers. Which plugs, punchdowns, wires, and connections you use in between the ends is your business, as long as the connections are fairly secure from EMI ingress, and the wire has at least 3 twists per foot, preferably more. You must maintain the pairs, and the polarity, obviously. Some transceivers will detect backward polarity, and reverse themselves to compensate. Regular "silver ribbon" telephone wire that they use to make desk-to-wall cords will cause collisions on a 10baseT connection. If anyone is interested, I can write a longer posting on the ins and outs of 10baseT, and the experiences I and my co-workers have had with it. -- Andrew C. Esh andrew@osa.com Open Systems Architects, Inc. Minneapolis, MN 55416-1528 So much System, (612) 525-0000 so little CPU time...
rainer@hwsw.gedas.de (Rainer Raupach) (04/04/91)
(stuff deleted) |> As to why 10BASE-T uses an RJ-45, I know of a couple of reasons, but I |> don't know that any of them are "official." First and most important, |> it's to keep people from plugging their phones into data jacks, and |> vice versa. Secondly, it's to allow for people in the future plugging |> their phones into data jacks, but making it work. You'll find that |> ISDN normally uses pins 4, 5, 7, and 8. |> |> -Bill Woodcock |> BMUG NetAdmin Additional to these reasons, there are some more: AT&T uses some more pins to include some other features, like SQE-testing and link integrity testing. I really don't know, if those features are part of the 10 Base T - standard. Rgds Rainer --- Rainer Raupach Internet: rainer@hwsw.gedas.de Network Coordinator X.400: S=RAUPACH C=DE A=DBP P=VW-GEDAS VW-GEDAS Berlin, GER Phone: +49 30 39007-629 / FAX : ext -999
andrew@jhereg.osa.com (Andrew C. Esh) (04/04/91)
From the response, both here and in EMail, this sounds like a really hot subject. I will put together as much as I can, and post it soon. -- Andrew C. Esh andrew@osa.com Open Systems Architects, Inc. Minneapolis, MN 55416-1528 So much System, (612) 525-0000 so little CPU time...
zeleznik@cs.utah.edu (Mike Zeleznik) (04/05/91)
In article <821@hwsw.gedas.de> rainer@hwsw.gedas.de (Rainer Raupach) writes: >(stuff deleted) > >|> As to why 10BASE-T uses an RJ-45, I know of a couple of reasons, but I >|> ... >|> BMUG NetAdmin > >Additional to these reasons, there are some more: >AT&T uses some more pins to include some other features, like >SQE-testing and link integrity testing. I really don't know, if >those features are part of the 10 Base T - standard. > >Rgds Rainer Are they using the extra pins to remotely control these features of the transceiver? Otherwise, I don't see the need for more lines/pins. I thought that link integrity is handled simply by transmitting a low-duty-cycle pulse on the xmit pair when there is no other activity, and seeing if it comes back on the receive pair. This would not require any additional lines/pins. The SQE signal, and the integrity test of its line, occur on the other side of the transceiver, so how would this require more lines/pins on the physical network? Mike Michael Zeleznik zeleznik@cs.utah.edu 801-581-5617
jbreeden@netcom.COM (John Breeden) (04/06/91)
In article <821@hwsw.gedas.de> rainer@hwsw.gedas.de (Rainer Raupach) writes: >(stuff deleted) > >|> As to why 10BASE-T uses an RJ-45, I know of a couple of reasons, but I >|> don't know that any of them are "official." First and most important, >|> it's to keep people from plugging their phones into data jacks, and >|> vice versa. Secondly, it's to allow for people in the future plugging >|> their phones into data jacks, but making it work. You'll find that >|> ISDN normally uses pins 4, 5, 7, and 8. >|> >|> -Bill Woodcock >|> BMUG NetAdmin > >Additional to these reasons, there are some more: >AT&T uses some more pins to include some other features, like >SQE-testing and link integrity testing. I really don't know, if >those features are part of the 10 Base T - standard. > RJ45s are used because the original concept of 10baseT was to use the exist- ing TELEPHONE wiring - and there's been a TELEPHONE wiring standard in use for years now .... AT&T's PDS (Premise Distribution System). PDS states that pins 4,5,7 & 8 are for voice and 1,2,3 & 6 are for data (pin 1 is on the extreme left when viewing a RJ45 head on with the little clippy thing pointing down). How prevelent is the use of this standard? Look at any install over the past 10 years of an AT&T, Northern Telecom or Rolm PBX and the wiring is PDS standard (I think these three should represent about 90% of the big PBX installs). The PDS wiring standard was also picked up as the wiring to the desk for ISDN (B channel). It also includes a "standard" for transporting both async and sync terminal traffic over the same 4 pair UTP. AT&T recently introduced a UTP "super wire" that they claim will transport 16 mb token ring for 300 feet using the same 2 data pairs. -- John Robert Breeden, jbreeden@netcom.com, apple!netcom!jbreeden, ATTMAIL:!jbreeden ------------------------------------------------------------------- "The nice thing about standards is that you have so many to choose from. If you don't like any of them, you just wait for next year's model."
cmilono@netcom.COM (Carlo Milono) (04/06/91)
First, as was stated in an earlier post or RE:, it is *not* true that AT&T uses more than the 4 wires for 10BASE-T - four is IT for the standard and their product is standard. Secondly, it is a misnomer to use the RJ45 name for an 8-pin jack - the correct terminology is the ISO 8877 jack. The RJ stands for Registered Jack and refers to those blocks that terminate a TelCo circuit as a demarcation point to a public service. You may note that if you have a DSU or Modem with a private line, that the connector looks a bit different, possibly with a switch-selectable resistor and it will have a notch on the jack as a key for the data-set plug. Lastly, you can run your 10BASE-T on household 'quad' wire and get an appropriate cord (twisted preferably) to splay the four wires into the 10BASE-T standard spacing within the ISO jack. I have several locations where the only wire available was a six-conductor wire split between two four-wire jacks - the first being a true RJ11. Works fine. I agree with a previous poster in that: 1) the physical arrangement allows for near foolproof use of a phone on the SAME jack (with a splitter) 2) the ISO jack has proven to be sufficient to support 3270, LAN, ISDN, Async, Sync, twin-axial (5251 - yuck!), as well as other less-used transmission schemes (Oh, LADC-II as well!) 8 pins will do most everything in a neat and clean manner, a la AT&T's PDS (as opposed to IBM's multi-gauge, shielded poop). -- +--------------------------------------------------------------------------+ | Carlo Milono: cmilono@netcom.apple.com or apple!netcom!cmilono | |"When a true genius appears in the world, you may know him by this sign, | |that the dunces are all in confederacy against him." - Jonathan Swift | +--------------------------------------------------------------------------+
andrew@jhereg.osa.com (Andrew C. Esh) (04/09/91)
In article <1991Apr5.105804.24270@hellgate.utah.edu> zeleznik@cs.utah.edu (Mike Zeleznik) writes: >> >>AT&T uses some more pins to include some other features, like >>SQE-testing and link integrity testing. I really don't know, if >>those features are part of the 10 Base T - standard. >> >>Rgds Rainer > >Are they using the extra pins to remotely control these features of the >transceiver? Otherwise, I don't see the need for more lines/pins. > >I thought that link integrity is handled simply by transmitting a >low-duty-cycle pulse on the xmit pair when there is no other activity, and >seeing if it comes back on the receive pair. This would not require any >additional lines/pins. > >The SQE signal, and the integrity test of its line, occur on the other side >of the transceiver, so how would this require more lines/pins on the >physical network? > >Mike > > Michael Zeleznik zeleznik@cs.utah.edu 801-581-5617 As far as I know, the above is correct. As a matter of fact, the Link Pulse is required in order to conform to the 10baseT spec. A hub that is in spec will not work with a transceiver that either does not do the link pulse, or has it turned off. "Twisted Pair" tranceivers, which are pre-10baseT will not work with the new hubs. All this occurs on pairs 1-2, 3-6 only, since that's all we bothered to punch down here. :-) -- Andrew C. Esh andrew@osa.com Open Systems Architects, Inc. Minneapolis, MN 55416-1528 (612) 525-0000 Practicing the OSI Standard
andrew@jhereg.osa.com (Andrew C. Esh) (04/10/91)
In article <1991Apr6.011139.1572@netcom.COM> cmilono@netcom.COM (Carlo Milono) writes: > > > >and their product is standard. Secondly, it is a misnomer to use the RJ45 >name for an 8-pin jack - the correct terminology is the ISO 8877 jack. The ^^^^^^^^ OK, got it... All I knew was RJ45, but in keeping with my good intentions toward solid international standards in technical communication, the above use is noted, and adopted. > >Lastly, you can run your 10BASE-T on household 'quad' wire and get an >appropriate cord (twisted preferably) to splay the four wires into the >10BASE-T standard spacing within the ISO jack. I have several locations >where the only wire available was a six-conductor wire split between two >four-wire jacks - the first being a true RJ11. Works fine. ^^^^ Huh? Now I feel ripped off. I learned "8-pin RJ45" = ISO 8877, but what is the ISO number for RJ11? Why wasn't it used here? I be confuse. >+--------------------------------------------------------------------------+ >| Carlo Milono: cmilono@netcom.apple.com or apple!netcom!cmilono | >|"When a true genius appears in the world, you may know him by this sign, | >|that the dunces are all in confederacy against him." - Jonathan Swift | >+--------------------------------------------------------------------------+ -- Andrew C. Esh andrew@osa.com Open Systems Architects, Inc. Minneapolis, MN 55416-1528 (612) 525-0000 Practicing the OSI Standard
andrew@jhereg.osa.com (Andrew C. Esh) (04/10/91)
Well, the boss put the kaibosh on the 10baseT soliloquy, so all I can do is comment on what you folks are talking about. No paper. Something about having to make money and selling information being our business, and all that. I suppose I can say a few things though. 10baseT is easier to install, requires less experience to connectorize, and is more fault tolerant than coax. It is not, as far as we can tell, being hyped by the box builders to generate sales, since we see a legitimate application for it. If you are going to do-it-yourself, make sure you are using cable that is really rated for 10baseT. I have seen so many wierdo cable type from non-descript manufacturers that does no do the job. This cheap stuff is exactly what the cable vendor and your boss with the checkbook are going to choose for you, so be ready with information. Don't even settle for a written guarantee from the cable vendor that it's good wire, since such a guarantee can rarely cover all the trouble and downtime necessary to replace bad cable. Don't go over spec. You need a certain number of twists per foot, and you can't run it further than 100 meters, so stick with it. Fudge, and you pay the price, or more specifically, you pay people like me to come fix it. Cards? We have had trouble with a certain vendor's card. My advice is: It's still early in the game. A few vendors still have cards that don't cut it. Get an in house demonstration from the vendor. They'll do it for free, if they think you're going to buy some cards. Run some data back and forth across them (a process I call flossing), and see if they work okay. The same goes for hubs. Usually a vendor will let you have a demo unit for a week. For PCs, you can use a 3c503 card with a small 10baseT transceiver plugged into the AUI port, and it runs just fine. 10baseT transceivers are getting smaller and cheaper. We have some that are about the size of a deck of playing cards cut in half. They're great. Be careful of EMI. About all I can say is that it gets into 10baseT more than the other cable types. It comes from some interesting places, many of which are common in an office environment. Test equipment? Yes. Use a pair tester. Use a cable scanner. That's about all I can say about that. Want some philosophy? 10baseT, ThinNet, ThickNet, and Fiber are all here to stay. They all have their applications, and none can completely replace any of the others. Add 10baseT to you list of solutions to apply. Networking is growing as we speak. There is a lot of work and discovery and development out there waiting to happen. I started out in Software Engineering, but now I have made the switch to networking, and I travel all seven layers of the OSI stack. I love it. Have fun ... -- Andrew C. Esh andrew@osa.com Open Systems Architects, Inc. Minneapolis, MN 55416-1528 (612) 525-0000 Practicing the OSI Standard
jcrowder@GroupW.cns.vt.edu (Jeff Crowder) (04/11/91)
In article <1991Apr9.224333.13034@jhereg.osa.com> andrew@jhereg.osa.com (Andrew C. Esh) writes: >stay. They all have their applications, and none can completely replace any >of the others. Add 10baseT to you list of solutions to apply. Networking is And THAT'S the Truth... Forget the rest of the rubbish. Andrew has it right. Jeff Crowder