dricejb@drilex.UUCP (Craig Jackson drilex1) (08/17/90)
We're looking at doing a major amount of unshielded twisted-pair wiring
here, and our wiring guys have heard about proposals to go over 10
megabits on twisted pair. What is the state of this? Is there a committee
looking at it, or something related (like shielded twisted pair)?
Are there any guidelines known today which would increase the likelihood
of the plant which we are about to install conforming to any faster
standard?
--
Craig Jackson
dricejb@drilex.dri.mgh.com
{bbn,axiom,redsox,atexnet,ka3ovk}!drilex!{dricej,dricejb}kwe@bu-it.bu.edu (Kent England) (08/18/90)
In article <14861@drilex.UUCP>, dricejb@drilex.UUCP (Craig Jackson drilex1) writes: > We're looking at doing a major amount of unshielded twisted-pair wiring > here, and our wiring guys have heard about proposals to go over 10 > megabits on twisted pair. What is the state of this? Have you been reading this list very long? :-) It's a done thing and it's called 10BaseT. Every Ethernet vendor and hopeful vendor is hard at work cranking out 10BaseT gear. > Are there any guidelines known today which would increase the likelihood > of the plant which we are about to install conforming to any faster > standard? > -- That is a good question. It has as much to do with installation practice as it does with quality of cable. I would recommend following a good structured wiring plan (like AT&T's) and buying AT&T spec cable. I don't think you can afford the new lo, lo, lo cap (and big, big, big bucks) cable. I know I can't pay that much for a dubious benefit. If you use a structured wiring plan, and AT&T DIW spec wire, then you can go 100m at 10Mbps and about the same at 16Mbps. Think on fiber for going 100Mbps. That is pretty good for wire that was spec'ed only out to 6Mbps. If you want 10BaseT on existing wire, then you had better plan on testing it. Test gear is under development and I have heard tell of some interesting hand-held units, but I don't have details. And don't ask about aging effects. Ten years after installing 10BaseT you might have to redo some installs, but I can't be sure how bad that could be. And who can look ten years ahead? :-) --Kent
cmilono@netcom.UUCP (Carlo Milono) (08/18/90)
Although there are vendors that are tinkering with >10Mb, they are not what you might call standard. ARCNET is planning/discussing a 20Mbps implementation, and there are informal committees meeting on that exact subject. CDDI, or FDDI for Copper is also being explored, and has been demonstrated by Bell Labs, and others. There is a problem with 100Mbps as it is being done today under FDDI - the current modulation scheme will violate FCC standards when used over STP or UTP. The basic harmonic is >30Mhz and is quite strong. There are other modulation schemes that will pack more data per cycle, and I believe the IEEE will be meeting on this soon. Higher grade copper plant is now being made available - AT&T introduced 2061 4 Pair DIW that will extend 10BASET beyond its current 100 meter limit. This same wire will also facilitate 16Mb Token Ring. -- +--------------------------------------------------------------------------+ | Carlo Milono | | Personal: netcom!cmilono@apple.com or apple!netcom!cmilono | | Business: cmilono@iliad.att.com | |"Sometimes I think the surest sign that intelligent life exists elsewhere | | in the universe is that none of it has tried to contact us." B.Watterson | +--------------------------------------------------------------------------+