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Homemade cat5 cable using existing phone line fails.

Ben Jackson said:
I've never seen solder type RJ45 connectors. You need a crimping tool.
For one cable it's not worth it. For many, it is.

No, it's not. Commercially manufactured patch cables are far more
reliable than home-made ones and no more expensive.

-Larry Jones

OK, what's the NEXT amendment say? I know it's in here someplace. -- Calvin
 
B

Ben Jackson

Jan 1, 1970
0
No, it's not. Commercially manufactured patch cables are far more
reliable than home-made ones and no more expensive.

Well, what I was trying to say is that if you can't amortize the cost of
a crimping tool over many cables, the one home-made one will cost more
than a manufactured cable. If you factor in the cost of tools, materials,
the yield rate and your time then it's never worth it to crimp your own
ethernet cables, as you point out.
 
S

Sam Nickaby

Jan 1, 1970
0
That's a telephone plug that's completely unsuitable for network use.
Do yourself a favor and go *buy* the patch cord you need, don't try to
make it yourself.

This plug has 8 terminals that matches the exact dimensions to a normal cat5
plug from what I'd measured using a precision caliper. If there is chemistry
involve that makes this unsuitable for network use then what will it be?
 
A

Al Dykes

Jan 1, 1970
0
This plug has 8 terminals that matches the exact dimensions to a normal cat5
plug from what I'd measured using a precision caliper. If there is chemistry
involve that makes this unsuitable for network use then what will it be?


The drawings in your PDF show too much untwisted wire to meet CAT5
spec. CAT 3 maybe, and it might work at 10MB.

Here's a pic. There's MUCH to MUCH untwisted wire.

http://www.systimax.com/pressroom/image_library/default.asp?img=39

Buy a real patch cable.
 
D

DecaturTxCowboy

Jan 1, 1970
0
Sam said:
This plug has 8 terminals that matches the exact dimensions to a normal cat5
plug from what I'd measured using a precision caliper. If there is chemistry
involve that makes this unsuitable for network use then what will it be?

Look REAL close at the gold plated tines. If the two or three are
offset, then its for solid conductor. If the two are in line, its for
stranded cable.
 
C

Carl Navarro

Jan 1, 1970
0
This plug has 8 terminals that matches the exact dimensions to a normal cat5
plug from what I'd measured using a precision caliper. If there is chemistry
involve that makes this unsuitable for network use then what will it be?

Thank Eli Whitney for that.

A 4 pin handset plug will fit in the jack, so why don't you solder
that up and use it?

The particular plug you refer to was designed a long time before
Cat-5e was a standard.

It's O.K. In fact, rather than use any kind of standard, take you 8
conductors and put them down in any color sequence you like. Just
match them on the other end and check them with a "tester" for
continuity. If it works, you did a good job. If it doesn't you can
post to 4 usenet groups and then argue with the standards.

Oh, you already did.


Carl Navarro
 
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Robert Redelmeier

Jan 1, 1970
0
In comp.dcom.cabling Sam Nickaby said:
This plug has 8 terminals that matches the exact dimensions
to a normal cat5 plug from what I'd measured using a precision
caliper. If there is chemistry involve that makes this unsuitable
for network use then what will it be?

The network "chemistry" is balanced signalling. It is the magic
that allowed clever network engineers to run 100 MHz over 100m
of wild country ten+ years ago when motherboard designers could
hardly get 50 MHz over 20cm on a PCB with unbalanced signals.

In this case, your plug has projections that may block other
ports or might not fit in the jack properly.

Less obviously, it has long parallel unbalanced conductors.
AKA "untwist". A crimped plug has about 1 cm of untwist.
This low-tool plug has at least 3 cm.

But this isn't as fatal as trying to run silver satin at 100 MHz.

-- Robert
 
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Rich Grise

Jan 1, 1970
0
Flat telephone cable (silver satin) isn't Cat-3 cable. It would be
known as voice-grade, rated good for maybe 5kHz. Cat-3 cable is round,
looks just like cat-5 normally, just not as many twists per inch.

It also depends alot on speed too. You can get away with alot for 10-Base-T.
With todays stuff being all 100-Base-TX or 1000-Base-T, the specs are
*alot* tighter.

Forgive me - I kind of lied. I dug out what's left of the 100-footer,
and it might actually be cat 3 - it's not the flat "silver satin"
stuff, it's round, and beige, with solid wire with about 1 or 2
twists per foot. The connectors, I scrounged from a previous installation
that they were trashing. They were crimped, on 8-conductor solid
(real cat 5) wire; I cut it off about 4" from the end, then cut
the 4 unused wires all the way back to the connector body, and
just twisted them together and wrapped black tape around them.

Worked fine, until somebody ran over it with the fork lift. )-;
And my laptop died, so there's not much point in wiring the trailer
any more. )-; )-;

Thanks!
Rich
 
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Jim

Jan 1, 1970
0
Sam Nickaby wrote on 3/11/2006 5:41 AM:
I made my own Ethernet cable to extend our DSL connections to
25 feet. I used a cat5 male connector on each end. I use two ordinary
phone line cords. After I lined them up identically like what cat5 cables
are supposed to I then solder and assemble the cords. I then check the
resistance on all eight terminals. They all check fine.

The problem is when I plug one end of the cable to DSL modem the other
to the PC the cable fails to work. I keep getting "network cable unplug" and
"network cable plug" consistently until I unplug the cable. Does this
mean that the cat5 won't accept the ordinary phone cables?

Thanks
Just get a couple of these and dont worry about where you put the DSL
modem.

http://www.netgear.com/products/details/XE102.php

Jim
 
Sam Nickaby said:
This plug has 8 terminals that matches the exact dimensions to a normal cat5
plug from what I'd measured using a precision caliper. If there is chemistry
involve that makes this unsuitable for network use then what will it be?

No chemistry, physics. There are *lots* of DC and AC electrical
properties that are every bit as important as the physical properties
for correct operation. Your plug is probably OK as far as the DC
properties, but there's no way it's going to come anywhere close to
meeting the AC properties required for a reliable 100BaseT connection.

-Larry Jones

Hmph. -- Calvin
 
S

SMS

Jan 1, 1970
0
Sam said:
I made my own Ethernet cable to extend our DSL connections to
25 feet. I used a cat5 male connector on each end. I use two ordinary
phone line cords. After I lined them up identically like what cat5 cables
are supposed to I then solder and assemble the cords. I then check the
resistance on all eight terminals. They all check fine.

A cable like that costs $3. Why are you doing this?

"http://www.computergate.com/products/item.cfm?prodcd=CNWTC4525W"
 
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James Thompson

Jan 1, 1970
0
DLR said:
Having a correct pin out doesn't a Cat5 cable make. It has to do with
signal handling. And this one will not pass muster.

Each wire pair in a cat 5 cable has a different number of twist, making each
pair have a different capacitance per foot. The regular phone wires have no
twist and no pair wires. The phone wires are meant to pass dc signals and
the cat 5 wire pass modulated frequencies, so without the wire pairs in the
cable with the twist - the 2 modulated frequencies crosstalk and interfear
with each other.
 
C

Carl Navarro

Jan 1, 1970
0
Each wire pair in a cat 5 cable has a different number of twist, making each
pair have a different capacitance per foot. The regular phone wires have no
twist and no pair wires. The phone wires are meant to pass dc signals and
the cat 5 wire pass modulated frequencies, so without the wire pairs in the
cable with the twist - the 2 modulated frequencies crosstalk and interfear
with each other.
Ya know, if you keep posting to this thread, you can make it to 4
months. The sad part is that Sam (the OP) is probably dead serious in
how he did this. Two 4C silver satin base cords shoved into a
retrofit 8C shell like we used for solid wire to an AT&T 8 pin plug
and when the tinsel wire wouldn't fit he used a soldering iron.

Sam, buddy, you goofed. In order to solder wires like that, you need
a telco approved soldering iron. Preferrably the 250 watt American
Beauty that we used on the frame. Your second mistake was that you
really only needed one base cord, since it only uses 4 wires. The
reason your setup didn't work is because, even though it passed
resistance tests, the wires are too small. Go down to the hardware or
big box store and get some doorbell wire. Two runs of that ought to
work just fine and get some tape so you can tape the 2 one pair cables
together, or look for 4 wire doorbell cable...if they make it.

Now, since you haven't troll^h^h^h^h posted in a few months, I'm
guessing that you figured out your error and everything is working
fine.

Carl "this is message 34 in the thread" Navarro
 
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Jeff Liebermann

Jan 1, 1970
0
Each wire pair in a cat 5 cable has a different number of twist, making each
pair have a different capacitance per foot.

The cazapitance per foot is about the same for each pair (I just
measured it on a 500ft roll) at about 30pf per ft. For CAT6, each
pair is solvent welded together at a constant distance making it
constant capacitance. The relatively loose twist rate does not
contribute any change in cazapitance.

The purpose of the different twist rates is to reduce coupling between
pairs. The basic specification is about 11dB NEXT or Near End Cross
Talk. The twisting drastically reduces the external coupling from
each pair. If the pairs were all wound at the same rate, they would
have a much larger number of points of contact between adjacent pairs.
It's these points of contact that cause the most coupling between
pairs due to simple capacitive coupling at the point of contact.
Reduce the number of points of contact and the coupling goes down.

By using non-twisted pair telco wire instead of CAT5, the worst case
cable is created. It has the maximum points of contact (the entire
length), the worst case NEXT as it makes a great distributed
transformer, and the worst loss because the non-twisted pairs will
radiate somewhat more.

I've actually seen commercial cables with such wiring. It's
legitimately CAT3 cable (which usually has a silver colored jacket)
and has 4 unpaired wires in the jacket. Some vendors (Asante) used to
bundle those with their MacIntosh ethernet (AAUI) adapters. I found
an entire skool computer lab connected with the junk. It works so-so
with 10baseT-HDX, but fails miserably with FDX (full duplex) or
100baseTX. I tossed something like 50 cables in the trash and
replaced them with home made CAT5 cables. Unfortunately, someone
fished them out of the trash and they found their way back all over
the skool. Sigh.

I've also used 25 pair telco wire for ethernet. That works just fine
for 10baseT-HDX, but also fails on the better or faster protocols.
Because it's twisted pairs, it doesn't leak too badly. Like the real
CAT5, the various pairs are twisted at different rates to reduce
crosstalk. I've never bothered too measure the impedance or NEXT as
I'm sure it varies and isn't even close to the CAT5 100 ohms. However,
it works well enough for 50ft or less runs.
 
S

Si Ballenger

Jan 1, 1970
0
Each wire pair in a cat 5 cable has a different number of twist, making each
pair have a different capacitance per foot. The regular phone wires have no
twist and no pair wires. The phone wires are meant to pass dc signals and
the cat 5 wire pass modulated frequencies, so without the wire pairs in the
cable with the twist - the 2 modulated frequencies crosstalk and interfear
with each other.

A single piece of four conductor cat3 phone wire can be used to
make a 10baseT ethernet connection. Pins 1, 2, 3, and 6 on the
RJ45 connector are used. I use this setup to connect to an old
computer in another part of the house. Below are some links
showing a four wire setup.

http://www.nullmodem.com/RJ-45.htm
http://www.xs4all.nl/~tcsprod/technics/rj45.htm
http://www.cisco.com/univercd/cc/td/doc/product/cable/cab_modm/ubr905/hig905/hig905ca.htm
http://www.infonewsindia.com/pinout/pinoutnetwork.html
 
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Doug McIntyre

Jan 1, 1970
0
Jamie said:
that's strange, our factory made Cat5 for years and still does on a
lower volume.
last time i checked, all pairs are twisted the same. and its the
differential TX and Rx that helps with the reduction of noise etc..

Did you ever look at it? The different TPI is pretty visable on any
cat5 I've installed/used over the years.

Lets just cut some open I have here and count?

Lets see, I cut off a 10" long chunk and in my sample I have..

Blue Pair = 1.0 TPI
Orange Pair = 1.3 TPI
Green Pair = 1.6 TPI
Brown Pair = 0.7 TPI

7 twists in 10" vs. 16 twists in 10" is pretty visable to me.
 
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Jeff Liebermann

Jan 1, 1970
0
Jamie said:
Doug McIntyre wrote:
yes, i have looked at it, i have maintain the machines and worked with
the management that are involved in getting the twinning machines
set up to run this product.
they are all twisted the same rate. the only difference is when the
pairs get bunched together, we have a process to make sure they are
coupled together at offset points.
it must work because it passes all test our engineering department
put on it along with QC.

Summary of EIA-568 at (because the EIA wants $750 for the printed or
CDROM version of the standard):
http://www.commserv.ucsb.edu/infrastructure/standards/history/EIA-TIA_568.asp
Pair Assembly
The pair twists of any pair shall not be exactly the same as
any other pair. The pair twist lengths shall be selected by the
manufacturer to assure compliance with the crosstalk requirements
of this standard.

Every CAT5 cable that I've worked with has had different twist rates
on each of the 4 pairs. ANSI/TIA/EIA-568 does NOT specify the twist
rate, but simply leaves it to the manufactory to optimize. If you can
meet it with identical twist rates, I'll be suitably impressed.
 
J

Jamie

Jan 1, 1970
0
James said:
Each wire pair in a cat 5 cable has a different number of twist, making each
pair have a different capacitance per foot. The regular phone wires have no
twist and no pair wires. The phone wires are meant to pass dc signals and
the cat 5 wire pass modulated frequencies, so without the wire pairs in the
cable with the twist - the 2 modulated frequencies crosstalk and interfear
with each other.
Hmm,
that's strange, our factory made Cat5 for years and still does on a
lower volume.
last time i checked, all pairs are twisted the same. and its the
differential TX and Rx that helps with the reduction of noise etc..
 
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