HDTenEightyP/NetNews huggingface dataset:
From: seifert@netcom.com (Rich Seifert)
Subject: Re: Wave shape and frequency of 10Base2
Organization: Netcom - Online Communication Services  (408 241-9760 guest) 
Date: Mon, 5 Oct 1992 23:49:15 GMT

In article <1992Oct5.172704.29003@ucsu.Colorado.EDU>, barr@tramp.Colorado.EDU (BARR DOUG) writes:
> I have been curious for some time now to look at an ethernet signal
> with an oscilloscope. I finally found time to do it and it is very
> interesting what I see. I put the probe on an open end of a 10base2
> (thinwire) connector. The scope is able to synch on 4 wave shapes
> These wave shapes are a 10Mhz sine wave, a second 10Mhz sine wave,
> 180 degrees out of phase. The other two waves are a 5Mhz wave and
> a second 5Mhz wave 180 degrees out of phase (these waves appear to
> have a sinusoidal rise and fall time with a straight line connecting the
> rise and fall). The four waves represent a 0 followed by a 0, a 1 followed
> by a 1, a 0 followed by a 1 and a 1 followed by a 0 (correct me if I am
> wrong). The amplitude of all the waves is from 0 volts to -2 volts.
> 
> 
> 

I suspect that you were either not synchronized to the signal, or
were looking at an unterminated end after a long run.

The signal waveshape on 10Base2 is the same as for 10Base5, and the
signals are (roughly) the same amplitude. This is a straight, 
Manchester-encoded signal, with approximately 25 ns rise and fall
times. It should look like a trapezoid near the driver, and a
degraded trapezoid farther away, possibily as bad as a sinusoid
after a few hundred meters of cable.

-- 
Rich Seifert                    Networks and Communications Consulting
seifert@netcom.com              (408) 996-0922
                                (408) 996-2860 FAX
"... specialists in Local Area Networks and Data Communications systems"
From: oberman@ptavv.llnl.gov
Newsgroups: comp.dcom.lans.ethernet
Subject: Re: another 10BASE-T <=> 10BASE2 connection question
Date: 29 Sep 92 15:55:48 GMT

In article <1992Sep28.022955.6501@tybse1.uucp>, swhite@tybse1.uucp (William C. "Spike" White) writes:
> I've been following this 10BASET <=> 10BASE2 discussion and am afraid
> I may have missed something.
> 
> We have a NeXT computer we want to hook up to a 10BASE-T LAN.  We're 
> purchasing a D-link hub and, since the NeXTstations don't come w/ a
> 10BASE-T connector, I have been assured by at least two separate distributors
> that I can purchase a $30 10BASE2-10BASE-T balun.  It would go on the back
> of the NeXTstation and do the impedance matching to allow me to connect to
> the existing 10BASE-T wiring.  
> 
> In fact, these items may have already been ordered.
> 
> Now I'm getting worried.  The original poster specifically stated that he 
> wanted the cheapest solution possible.  Will this balun approach not work?  I
> KNOW a AUI-to-thinnet transceiver will work, but this is a pilot,
> proof-of-concept project I'm doing here and I need the cheapest reasonable
> approach. 

It will most likely work OK. You are technically doing something that is not
allowed (converting between different backbone media without a repeater), but,
in fact, if you have only one device attached to the coax section, it will
probably work. But there is more difference between 10base2 and 10baseT than
impedence. Collision detection is something to watch very closly, especially if
the network is large and you have multiple hubs and long runs.

I have learned (often the hard way) that non-standard solutions often come back
to haunt, so I don't recommend this type of solution. I also try to keep a
close eye on non-conformant equipment, because that is where things usually
flake out. I still suffer occasional problems from a vendor's non-standard thin
to TP product we installed several years ago. Every time I think I've removed
it all from service, another one of those baluns pops up. (Gee, maybe they can
pass genetic information across the net and are reproducing? :-)  )

But those were far shakier in design from what you are talking about, even if
they were sold by two of the big names in 802.3 equipment. So caveat emptor!
Keep all of the paperwork just in case you need to send it all back. (But you
probably won't have to.)

R. Kevin Oberman			Lawrence Livermore National Laboratory
Internet: koberman@llnl.gov		(510) 422-6955

Disclaimer: Don't take this too seriously. I just like to improve my typing
and probably don't really know anything useful about anything.
From: rkd@pt.com (Ray Downes)
Newsgroups: comp.dcom.lans.ethernet
Subject: Re: Good, but small RJ45 plugs ??
Date: 2 Oct 92 17:18:06 GMT
Organization: Performance Technologies, Incorporated

In article <fontaine-011092111216@130.104.58.15> fontaine@sri.ucl.ac.be (Alain Fontaine) writes:
>We used to terminate UTP with RJ45 plugs made by Thomas & Betts, and
>called 'Narrow IDC plug'. Up to know, those plugs fitted nicely in the
>jacks of all the UTP based equipment we used. We now have found some
>hubs where the RJ45 sockets are included in a single 'strip', and the
>'narrow' plugs are not narrow enough anymore (let's say that they are
>less than a millimeter (or 1/32") too wide - I mean the part of the
>housing that stays outside the RJ45 jack).

I assume you were using the T&B IDC narrow plug, p/n 009-7-880-X1
(beige in color). I have some patch panel cable made with these - found
they wouldn't fit in AT&T Starlan-10 hubs (metalwork clearance
problems), so I used AMP modular RJ45 plugs in place. These are
available of course via AMP (sample some to verify fit), or for about
$.30 (qty 1-99) each via places like Altex Electronics (800) 531-5369
(p/n MP-8).  If you elect to use these connectors note that they
require a crimping tool ($15 for a cheapie - $130 for a hight quality
AMP handtool).

>So the question is: does anyone know plugs suitable to terminate
>twisted pair cables, high quality but narrower than narrow ???

The AMP RJ45 plugs are no wider than the inside of the socket ...
-- 
Ray Downes, Performance Technologies Incorporated		rkd@pt.com
315 Science Parkway, Rochester, New York 14620		  
Voice - (716) 256-0200, FAX (716) 256-0791
From: seifert@netcom.com (Rich Seifert)
Newsgroups: comp.dcom.lans.ethernet
Subject: Re: Transceiver Monitor
Keywords: ethernet, transceiver, monitors
Date: 30 Sep 92 23:11:19 GMT
Article-I.D.: netcom.1992Sep30.231119.26131
Organization: Netcom - Online Communication Services  (408 241-9760 guest)

In article <1992Sep28.145811.23668@walter.cray.com>, rjohnson@eastrg1.cray.com (Richard Johnson) writes:
> I would like to build a simple inline transceiver monitor, with leds for power, collision, xmit, and rcv. Can I just
> hang a led with a resistor accross the appropriate pins 
> of the DB-15 (MIL-C-24308 or equiv) ?? 

No. The signals on the AUI interface are differential ECL. The
total signal swing is only a volt or so (worst-case). You can
put an LED/resistor on the power pair, to determine if there is power.

You could build a simple circuit (powered from the power pair)
that looks at the other signals and derives LED drive from them.
I think such devices are available from a few companies.

-- 
Rich Seifert                    Networks and Communications Consulting
seifert@netcom.com              (408) 996-0922
                                (408) 996-2860 FAX
"... specialists in Local Area Networks and Data Communications systems"
Newsgroups: comp.dcom.lans.ethernet
From: mack23@avalon.eecs.nwu.edu (Chris Walsh)
Subject: Re: Ethernet address of 00: 00:00:00:00:00
Organization: My desk in the Tech building
Date: Thu, 1 Oct 1992 21:12:25 GMT

In article <booth.13.0@lub001.lamar.edu> booth@lub001.lamar.edu (John Booth) writes:
>
>An all Zeros Ethernet Address is a type of broadcast used by Sun workstations
>and other (older) TCP/IP implmentations. The standard now is pretty much 
>all ones (FF:FF:FF:FF:FF:FF), although most TCP/IP implementations will 
>still give you a choice between the two. 

Don't you mean that the IP broadcast mask for BSD4.2 used to be all zeroes
in the last octet (eg. 128.135.252.0), but would now be all ones?

The original poster is talking about an ethernet (MAC level) address,
not an IP address.

Maybe I'm missing something.

Chris
Newsgroups: comp.dcom.lans.ethernet
From: ddaum@magnus.acs.ohio-state.edu (Dana Alan Daum)
Subject: Re: Renting Cable Testers (Microtest)
Followup-To: poster
Organization: The Ohio State University
Distribution: usa
Date: Tue, 6 Oct 1992 16:55:53 GMT

In article <BvG6rK.E7n@chinet.chi.il.us> djc@chinet.chi.il.us (David J. Carpenter) writes:
|
|Does anyone know where I would be able to rent a cable tester?
...
|David Carpenter
|uunet!chinet!djc
|(312) 625-0462

Try COMBYTE USA, Dan Ebert, 800/446-3634.  They have (or at least used to
have) a program where you could lease a cable tester, with the lease cost
going towards the purchase price should you decide to buy it.  I believe
they have the full range of Micro Test scanners.

Dana.
dad+@osu.edu
Organization: The American University - University Computing Center
Date: Thu, 1 Oct 1992 12:44:04 EDT
From: <DRASCH@auvm.american.edu>
Newsgroups: comp.dcom.lans.ethernet
Subject: Re: ? Relating collision, utilization rates

Martyn:

Which number to you think is out of wack the 35% utilization of the 1 % of coll
ision?  The numbers seem about right to me.  How many nodes are on the segment,
how many hosts, etc.  That would help judge the volume.  You can also look at
the dump to see the collision and packets coming across the wire.

A LAN Analyzer is a great tool, have fun!
Newsgroups: comp.dcom.lans.ethernet
From: Pressley@vxc.uncwil.edu (Mike Pressley)
Subject: Screen control software over Ethernet
Keywords: screen,control,ethernet
Organization: Academic Computing Services
Date: Tue, 29 Sep 1992 17:13:49 GMT


We are in the process of setting up a multi location network
in a class room configuration. The only problem is we want
to be able to login to any station on the net, place it in server
mode and display its screen on every machine on the net. We
are going to be using high resolution graphics, therefore this
communication package must run on ethernet. Basically we
are looking for a PC-Anywhere or Carbon Copy product that
runs on ethernet and has one server controlling several
nodes.

If anyone has any idea where to purchase this product or if
such a product exists, Please send me E-mail. Thanks very
much.

Mike Pressley
Academic Computing Services
UNC Wilmington
pressley@vxc.uncwil.edu
jmp@ecsvax.uncecs.edu
From: petert@logitek.co.uk (Peter Telford)
Newsgroups: comp.dcom.lans.ethernet
Subject: Reserved addresses.
Summary: What are these reserved addresses for?
Keywords: ip, reserved, tcp
Date: 30 Sep 92 08:04:00 GMT
Organization: Logitek Plc.

Hi,

One of my ex-colleagues has asked me to post the following 
question:

"Why are some internet addresses reserved?"

If anyone could help my colleague please email me your
answer at peter@logitek.co.uk

Thanks in advance.

PT.
Newsgroups: comp.dcom.lans.ethernet
From: djc@chinet.chi.il.us (David J. Carpenter)
Subject: Renting Cable Testers (Microtest)
Organization: Chinet - Public Access UNIX
Date: Thu, 1 Oct 1992 14:54:56 GMT


Does anyone know where I would be able to rent a cable tester? I need something
to verify some twisted pair wiring for 10BASE-T, and all of the units I have
seen advertised have been at least $1,000.

Thanks.

David Carpenter
uunet!chinet!djc
(312) 625-0462
From: moore@raleng.mtc.com (Dave Moore)
Newsgroups: comp.dcom.lans.ethernet
Subject: Surge protection for ThinWire
Date: 2 Oct 92 19:01:03 GMT
Organization: Memorex Telex, Raleigh, NC

We've got a ThinWire segment of our Ethernet running underground through PVC pipe a couple
hundred feet to a seldom used machine in a small building beside our main building.  Twice
this summer the Ethernet card in that machine fried mysteriously while the machine was
unattended and powered off.  Suspicions have fallen on lightning or some other surge
coming in on the ThinWire, as nothing other than the Ethernet card has been damaged.
The multiport repeater, a Allied Telesis Centrecom 3008, which is at the other end of the
wire, has not suffered any damage.

To all you Ethernet gurus out there, does our lightning theory seem plausible?  Does
anybody have any experience with surge protectors on ThinWire segments?  I've seen such
things in a couple of catalogs and was wondering if they really work.  Any input would be
appreciated.  Thanks.

Dave Moore
Memorex Telex
moore@raleng.mtc.com
Newsgroups: comp.dcom.lans.ethernet
From: pwilson@gandalf.ca (Paul Wilson(Toronto-Sales))
Subject: Re: 10BaseT != 3-Com Multiconnect (interesting stuff)
Organization: Gandalf Data Ltd.
Distribution: na
Date: Tue, 6 Oct 1992 00:58:58 GMT

In <1992Oct2.203308.2239@vogon1.pasen.gov> jdm1@vogon1.pasen.gov (Jonathan D McCown) writes:



>We have run across an interesting characteristic of the 3Com Multiconnect
>repeater (10BaseT Hub extrordinaire).  Apparently the Multiconnect hub
>was designed before the 10BaseT Standards were finalized, and while the
>Multiconnect is compatible with 10BaseT: IT HAS PHENOMINAL RUN LENGTH
>CHARACTERISTICS WHEN USED WITH 3COM NICS.  (much better than other
>"standard 10BaseT" equipment that we've tested).

>Despite the  whining of our 3Com reps that we shouldn't mess with such
>things, it is a fact of life that not all cable runs are short, nor is it
>very easy to get permission to string cable in historical buildings.
>We've driven runs up to 650' reliably (we use a router at one end) without
>problems using Multiconnects-- futility incarnate with other gear.
>It is also interesting that these runs are over telco 200 pair trunks :-)
>The docs rate Multiconnect 10BaseT up to 200m.  (We need every inch) 

>The Multiconnect manual lists separate distance specs for "3Com" and
>802.3 in all categories of Ethernet (base T,5,2 not BROAD) which basically
>DOUBLE the distances set by the spec.  Maybe this is one for alt.conspiracy.

This raises an issue which I have wondered about for some time, because
I am aware that other vendor's equipment (Gandalf, for example) exhibits
similar characteristics.  But isn't there a tradeoff with propogation 
delay?

Within ethernet, so I've always suspected, there are some hard and fast
rules about length of segments of thicknet, numbers of nodes per segment,
number of repeaters between two nodes, etc. and I always thought they 
were there for a good reason, though it may not be apparent at the time.
One such rule seems to relate to the length of cable/number of repeaters
between the two furthest nodes, stating that it shall not exceed a certain
distance, and this distance can ultimately be translated into propogation
delay.  In summary, "Thou shalt not have two nodes a distance apart such
that a signal shall exceed **** seconds propogation time."  Is my idea
correct?

If this is so, then the above scenario is an acceptable one iff the network 
trades off these extra long runs by not having more than, oh say 2 repeaters
between the furthest nodes (just pulling numbers out of thin air for this).
The only way to be really sure is to take the above **** time, and ensure
that the propogation through the wire, plus the other wires, plus the 
repeater propogation time, etc, doesn't exceed it.

While were on this topic, If my assumption is correct, where does the
time value mentioned above come from?  I'd really like to know.


--
Paul Wilson 416 698 3649
pwilson@gandalf.ca
Newsgroups: comp.dcom.lans.ethernet
From: gary@sci34hub.sci.com (Gary Heston)
Subject: Re: Who makes 10BaseT<->10Base2 repeaters?
Reply-To: gary@sci34hub.sci.com (Gary Heston)
Organization: SCI Systems, Inc., Huntsville, Al.
Date: Fri, 2 Oct 1992 15:41:41 GMT

In article <BvGzpM.Cp1@mudos.ann-arbor.mi.us> mju@mudos.ann-arbor.mi.us (Marc Unangst) writes:
  [ working on 10BaseT cards ]
>Unfortunately, our in-house network is still 10Base2, and we don't
>have any plans to change it in the near future.  This causes problems
>when us folks in tech support want to test a 10BaseT card, since we
>don't have any place to plug it in.  A full-fledged 10BaseT hub would
>be overkill, since we really only need to connect one 10BaseT card to
>the 10Base2 network at a time, and don't need to interconnect 10BaseT
>cards.

If there's the slightest possibility that you will be expanding your 
in-house net in the near future, go ahead and install a real hub. You
can then add future connections with 10BaseT, phase your existing stations
to it as the existing cards fail or get upgraded, and you'll have your
test drops. It'd also help sales to be able to show customers that you
use what you recommend.

>    It would be much better if we could get some sort of
>repeater-type device with a 10Base2 BNC on one end and a 10BaseT RJ-45
>on the other.  [ ... ]

Yeah, but... This approach will cost at least 1/3 what a 12-port hub
runs, and only provide one connection. I.e., you'll spend about $220
for one drop, instead of $650 for 12.

>Unfortunately I have been unable to find any such device.  Does
>anybody have some specific brand/model recommendations?  Does anybody
>know about how much we should expect to pay for such a device?

Well, let's look at the _Lan Times_ '92 Buyers' Directory Issue...

Addtron Technology has a UTP-4EA small hub that has one BNC and 4
	RJ-45 connections; $295. Call (510) 770-0120

There are a bunch of 8 port hubs around $500 (list) and 4 port cards....

If you're going to spend money, might as well get a real hub and 
plan for expansion.


-- 

Gary Heston    SCI Systems, Inc.  gary@sci34hub.sci.com   site admin
The Chairman of the Board and the CFO speak for SCI. I'm neither.
"...I looked out my window, and saw Kyle Pettys' car upside down, then I
Newsgroups: comp.dcom.lans.ethernet
From: gary@sci34hub.sci.com (Gary Heston)
Subject: Re: Renting Cable Testers (Microtest)
Reply-To: gary@sci34hub.sci.com (Gary Heston)
Organization: SCI Systems, Inc., Huntsville, Al.
Date: Mon, 5 Oct 1992 18:38:24 GMT

In article <BvG6rK.E7n@chinet.chi.il.us> djc@chinet.chi.il.us (David J. Carpenter) writes:

>Does anyone know where I would be able to rent a cable tester? I need something
>to verify some twisted pair wiring for 10BASE-T, and all of the units I have
>seen advertised have been at least $1,000.

Interesting, the MicroTest QuickScanner will check 10BaseT wiring (although
the thing for terminating the other end is a little awkward), and it's $995
list. Not "at least" a thousand.

I suppose you could request one for a 30-day evaluation.... But really, they're
well worth the cost. Mine has saved countless hours; it's so nice to plug
in and see "OPEN at 265'". 

Remember, people sitting idle while a cable is down costs money, and the
more people sitting through an extended outage resulting from a cable 
problem. Payback time can be just a few outages.


-- 
Gary Heston    SCI Systems, Inc.  gary@sci34hub.sci.com   site admin
The Chairman of the Board and the CFO speak for SCI. I'm neither.
"...I looked out my window, and saw Kyle Pettys' car upside down, then I
thought 'One of us is in real trouble'." Davey Allison, re: a 150MPH crash 
Newsgroups: comp.dcom.lans.ethernet
From: schenke@ferranti.com (dick schenke)
Subject: Re: ? Relating collision, utilization rates
Organization: Ferranti International Controls
Date: Tue, 6 Oct 1992 04:32:35 GMT

If your LANalyzer is connected to a transceiver through a DELNI
(or other type of 'AUI fanout unit')
then every SQE test by the other stations on the same transceiver will
count in the "Local Collision/SQE" total.  The documentation from Novell
discusses this (version 3.11 does, anyway).  Perhaps the higher collision
rate is measured on such a transceiver and the low rate location has
a transceiver to itself, or has a station with a low transmit rate on
the same transceiver.

We were deceived by this problem for a while.  An alternate way to
count local collisions without SQEs is to set up a transmission
test at a low rate (about 1% utilization) and count how many transmissions
result in deferral or collision.

Dick Schenke      Schenke@Ferranti.com
Ferranti International Controls      (713) 274-5469
Sugar Land TX USA
From: kcone@ncrclm.ClemsonSC.NCR.COM (Kevin Cone)
Newsgroups: comp.dcom.lans.ethernet
Subject: Re: 10baseT Level V cable problem
Keywords: UTP Level V
Date: 2 Oct 92 14:23:00 GMT
Reply-To: kcone@ncrclm.ClemsonSC.NCR.COM (Kevin Cone)
Organization: NCR E&M CLEMSON Liberty, SC

In article <J.Newman.148.717906276@icarus.curtin.edu.au> J.Newman@icarus.curtin.edu.au (John Newman) writes:

>I have been discussing UTP Level V cabling with one of
>our cable suppliers. He has presented us with a possible
>problem:
>His claim is that there are currently two "versions" of level V
>UTP cable:
>
I think this is the second or third time I've seen Level V cabling
mentioned in the context of Ethernet.  Unfortunately I don't have any
idea what is meant.  Can anyone out there shed some light on the subject?
-- 
Kevin A. Cone                           e-mail:  Kevin.Cone@ClemsonSC.NCR.COM
Consultant Engineer                     s-mail:  7240 Moorefield Hwy.
NCR Workstation Products Div.                    Liberty, SC  29642
phone:  803-843-5085 (VP 624-5085)      fax:     803-843-1793 (VP 624-1793)
From: seifert@netcom.com (Rich Seifert)
Newsgroups: comp.dcom.lans.misc
Subject: Re: T1 and LAN performance..??
Date: 27 Sep 92 16:52:19 GMT
Article-I.D.: netcom.5r#pp_g.seifert
Organization: Netcom - Online Communication Services  (408 241-9760 guest)

In article <1992Sep24.204418.936@mdd.comm.mot.com>, pchan@mdd.comm.mot.com (Pat Chan) writes:
> I've two Ethernet LAN's (10Mbps) connected together through 
> bridges and dedicated T1 (~1.5Mbps), as follows:
> 
>        LAN A           T1          LAN B
>     --------- Bridge ------ Bridge------------
> 
> I've a file in LAN A. Say an application (in LAN A) requires 
> w seconds to retrieve this file. 
> Does it mean that an application requires w*10/1.5 seconds 
> to retrieve the file from LAN B????

This is a wonderful question!! It forces us to look at what is 
really going on.

In the initial case (file transfer on a single LAN segment), the
length of time to transfer the file is a function of:
   -The performance of the application responsible for the file transfer
    (e.g., the FTP implementation)
   -The transfer rates of the disks themselves on the two machines
   -The protocol overhead in the two stations (IP, other NOS services)
   -The device drivers for the NIC cards
   -The NIC cards themselves
   -and finally the tranfer rate of the Ethernet.

As may be becoming obvious, in most situations, the Ethernet is the
least of your bottlenecks. I know of very few applications (and file
transfers with normal NOS's are not among them!) which can keep
an Ethernet busy. (NFS diskless workstations and DEC Local Area VAXclusters
are exceptions.)

Soooo, when we move the file to the other side of this WAN bridge, we
add a few things to the delay:
   -The store-and-forward time of the two bridges
   -Queueing delay in each bridge (dependent on offered load)
   -transmission time on the intervening link

The transmission delay on the T1 is 10/1.5 longer than than on the
Ethernet, but queueing delay probably dominates, unless traffic is
quite light. In any case, the transmission delay is probably still 
much less than the processing delays encountered in the original case.

The good news is that, while performance will be worse in the second case,
it is not be a factor of 10:1.5   The bad news is that the performance
was probably lousy in the first case.

-- 
Rich Seifert                    Networks and Communications Consulting
seifert@netcom.com              (408) 996-0922
                                (408) 996-2860 FAX
"... specialists in Local Area Networks and Data Communications systems"