Slashdot Log In
Handmade vs. Commercially Produced Ethernet Cables
Posted by
CmdrTaco
on Mon Apr 27, 2009 08:35 AM
from the now-wait-a-minute dept.
from the now-wait-a-minute dept.
An anonymous reader writes "We have a T1 line coming into our satellite office and we rely fairly heavily on it to transfer large amounts of data over a VPN to the head office across the country. Recently, we decided to upgrade to a 20 Mbit line. Being the lone IT guy here, it fell on me to run cable from the ISP's box to our server room so I went out and bought a spool of Cat6. I mentioned the purchase and the plan to run the cable myself to my boss in head office and in an emailed response he stated that it's next to impossible to create quality cable (ie: cable that will pass a Time Domain Reflectometer test) by hand without expensive dies, special Ethernet jacks and special cable. He even went so far as to say that handmade cable couldn't compare to even the cheapest Belkin cables. I've never once ran into a problem with handmade patch cables. Do you create your own cable or do you bite the bullet and buy it from some place?"
Related Stories
Submission: Handmade vs Commercially Produced Ethernet Cables by Anonymous Coward
This discussion has been archived.
No new comments can be posted.
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
Full
Abbreviated
Hidden
Loading... please wait.
How much is your time worth (Score:5, Insightful)
Re:How much is your time worth (Score:5, Informative)
While it may be cost effective to crimp and cut your own cable when you are making less than 20 dollars an hour once you are making 20 dollar+ just buy it.
I promise you I can make more than $20 worth of test-worthy cables in one hour.
Parent
Re:How much is your time worth (Score:5, Interesting)
I promise you I can make more than $20 worth of test-worthy cables in one hour.
I'll second that. I make my own cables when I want a specific length, rather than having the extra wire coiled up in a cable tie.
-jcr
Parent
Re:How much is your time worth (Score:5, Funny)
Yeah,
But the occasional dud-job does pass by. Then you've got this thing spraying ether all over the walls, the floors, and what-have-you.
Try explaining that one, passing the hallway, with ether dripping from the front of one''s trousers. "It's my handworked cable, you see..." you might mumble to colleagues, to their dubious glances.
I know a lot of you came up while 10 MbPS was standard. The drizzling or atomizing was even comforting - almost acceptable in Cat5. Now, 100 MbPS goes off like a water-cannon. With Gig arriving to the desktop and commodity rack, I don't know if "grow-your-own" is advice that one may any longer advocate with a dry lap or chin!
Parent
Re:How much is your time worth (Score:5, Interesting)
1. Amateur cable. These are done just any old way as long as the colors match at both ends. The pairs don't even have to be twisted for it to work over very short distances (2 to 6 feet) at 1GB.
2. Professional Cable. All the pinouts done properly according to whichever standard you are working with, by someone who knows what he is doing.
3. Factory cables. Here is the dirty secret. Some of these are done by robots and some are just professional cables. There is no way for you to tell which is which.
Now to your specific problem. If your boss insists on paying $300 for $20 worth of cable just to satisfy his own misguided notions of quality, you as the highered help just have to accept his decision and go cry into your beer.
Or better yet. Smile. they had no intention of using the money you would have saved to enhance your salary.
Parent
Re:How much is your time worth (Score:5, Insightful)
Parent
Re:How much is your time worth (Score:5, Informative)
Orange and white, Orange. Green and White, Blue. Blue and White, Green. Brown and White, Brown.
Use pieces (cable, plugs, jacks) certified for the speed you want to carry.
Once you get those two down, understand not to untwist more of the cable than absolutely necessary to get it into the connector, get it correctly into the cable, and get a good solid crimp on it - and TEST IT after you crimp both ends - odds are it's more than sufficient to carry as much GigE traffic as you care to move.
Once you have a stock of pieces on the shelf, it's WAY more cost effective from an employers perspective to make a single cable than to sit down, fill out a purchase order, have that purchase order pass through several hands during processing, follow up with the paper order, wait a week to have that single cable shipped to you. ESPECIALLY if that cable is a statistical anomaly and needs to be replaced.
If you're wiring a patch panel for the first time, however, order a hundred or so cables of various length and save yourself the hassle.
Parent
Re:How much is your time worth (Score:5, Informative)
I can't agree with this - if the termination of a transmission line is correct at each end, then the length has no matter at all for any frequency (in theory, not accounting for increasing losses with frequency, but then there's a reason for length restrictions in the CatX/Ethernet standards).
If you're talking about a *tuned* line (eg a stub or a tuned antenna feeder), then length is important. But we're not. If you've got problems with harmonics or matching and reflections then your ethernet cards are probably bottom-shelf knock-offs.
The problem with premade-lenght cables is you're going to run into tangles if many changes are made, and are going to end up coiling. Make that coil too tight and you're going to cause crosstalk. A custom job with all cables neatly following defined routes with no coils, twists or kinks is going to make life easier in the long term.
Parent
Re:How much is your time worth (Score:5, Funny)
Parent
Re:How much is your time worth (Score:5, Funny)
Damn, my mod points expired.
As another EE (who does all their work at about 3GHz), I must say you need to be modded to oblivion for that comment.
Please, just stop.
Parent
Not as such... (Score:5, Insightful)
They are made at specific lengths for marketing reasons. All of the "transmission line" characteristics of Ethernet cable have been solved for every length within the specified maximum.
I have a whole data center (~32 rows of 22 racks) fully cabled with lengths ranging from 100 meters to 5 inches (crossover between 1U boxes). They are cut to custom lengths, source to destination. Where their port is on the router and where they were placed in the tray add and subtract inches here and there. They run to the patchpanels in bundles about 7 inches in diameter. We have no problems with crosstalk, reflections, intermod and what have you.
If this were coaxial Ethernet we could have a fun discussion... but those days are well behind us.
Parent
Re:How much is your time worth (Score:5, Funny)
"If you've taken physics especially emf harmonics, you'd know wanting a specific length without considering harmonics is all kinds of bad because it may result in emi emission,"
Let me guess... you work for Monster Cable, in marketing perhaps?
Parent
Re:How much is your time worth (Score:5, Insightful)
Uh, what part of unshielded twisted pair don't you understand? The whole idea of the twists assuages any reasonable amount of both reception and transmission externally. Modern endpoint tranceivers are really good at signal to noise problems; you can usually make cables quite a bit longer than the IEEE specs call for with total impunity. And Cat6 isn't necessary, either, just quality Cat5/5e is fine.
The only place where fast transmission cables have problem with Ethernet is at the connectors. Crosstalk there, and ONLY THERE, can be a problem unless you do something pretty unnatural to the cable. RJ-45s simpily suck because of the parallel tines. Crimp according to directions. Takes about 30sec a side. If you're worried, shoot a TDR down the line. Fluke and others make some pretty cheapo testers, or bug a cable guy to test it for you. This is not rocket science. Don't wimp out and have someone else do it. Buy quality connectors and cable, and just do it. Get the color code, follow it, and move on.
Parent
Re:How much is your time worth (Score:5, Insightful)
>Welcome to the real world, where standing waves on transmission lines do exist, and you can choose lengths carefully based on the frequency going down it.
That may be true for RF, but the whole point of communication is that you get more than a single frequency - a frequency spectrum. So matching your cable length is no good for Ethernet.
In practice, there are hardly issues with standing waves, because the cable is unidirectional. So two reflections have to occur, and there is additional damping in the cable. So unless your impedance is way off, you should be fine. Even a 10% mismatch is perfectly harmless.
Parent
Re:How much is your time worth (Score:5, Funny)
No, you want to avoid those integer (or half) multiples of your wavelength to avoid setting up standing waves due to reflections in the cable. So go and trim a couple of picometers off those cables you just built and you'll be good to go.
Parent
Re:How much is your time worth (Score:5, Funny)
I don't see anything 'round' about your distances of 1.8288222384784 and 3.0480370641307 metres.
Parent
This is not a time/money issue (Score:5, Insightful)
This is a CYA issue. Your boss does not want to explain to HIS boss, when a cable goes bad and the company is losing $large_number per hour until it is diagnosed and fixed, that he authorized one of his tech guys to use "homemade" cables.
Parent
Re:How much is your time worth (Score:5, Insightful)
time out! How does making one cable run constitute reason for determining ROI on making cables based on cables per hour etc?
There are some of us who can whip out a standard 15ft Cat5 cable in about twice the time it takes to unwrap a commercially purchased cable. If you need custom sized cables, it's far easier and cheaper except for very small number of situations. If you have one cable run to do and the parts available, it makes no sense to go buy one. It's not like you're going to run out and get a 39 meter Cat6 cable at lunch time in the Mall.
Now, if you need 50 of them? perhaps a different story, but same story goes when you need 5000 of them. Savings get bigger with bulk. In this case, it was for a single cable. My suspicion is that his boss has never actually seen a well made cable created in front of his eyes. Remember grasshopper, all great Samurai swords were made by hand, not a machine with expensive dies.
Whatever happened to quality custom workmanship? It's almost as if people expect that it can't be done anymore? WTF?
Parent
Re:How much is your time worth (Score:5, Insightful)
It depends on the situation and the reason for the cable.
Sometimes there are restrictions for routing the cable that makes a prefabricated cable unusable.
And you may sometimes run into problems with a handmade cable, but often it does work just fine. If you get problems - just remake one contact at a time. If you have a decently modern intelligent switch you can also monitor the port for data errors, and if you don't have any errors it's good enough.
As for cabling quality - all the outlets in buildings are usually contacted by the cable jocks from the installation company and they do a simple test and then moves on to the next. I doubt that the quality from a hand made cable and those outlets are much different.
Parent
Re:How much is your time worth (Score:5, Funny)
audio grade Ethernet cables
Yeah, I have those. I keep it next to my hydrogen grade garden hose, and my lava grade plumbing.
Parent
Always buy them (Score:5, Interesting)
Agreed. (Score:5, Informative)
Yes, you can use handmade cables that are as good as mass-produced factory cables. But that really isn't the issue.
It's just not worth the time spent to cut and crimp your own lines anymore. In my experience, it was a more common practice years ago in IT. That may have had something to do with the fact that there weren't nearly as many PC's or ethernet ports in buildings as there are today.
My advice: Find a good supplier (i.e. not one that charges $800 for a 6 ft. adamantium-coated cable) and do something else with the rest of your time.
Parent
Re:Always buy them (Score:5, Informative)
Depending on wages and such, the commercial cables could easily have 10x the labor and still be cheaper.
Parent
meh, easy... (Score:5, Funny)
Re:meh, easy... (Score:5, Funny)
Hey, I just spent $100 on a 3ft gold-wired Cat6 cable, and I can tell that my bits are coming in cleaner.
Parent
Re:meh, easy... (Score:5, Funny)
Hey, I just spent $100 on a 3ft gold-wired Cat6 cable, and I can tell that my bits are coming in cleaner.
I hate to tell you, but the gold plated wire is doing nothing for you. The secret is in the directional indicator [denon.com]. That's where the magic happens.
Parent
Re:meh, easy... (Score:5, Funny)
Nah, I tested some ethernet cables I made with 4 pairs of wire coathangers and they performed just as well as the Monster Cable ethernet cord!
Parent
Re:meh, easy... (Score:5, Funny)
What a bunch of crap. My data transfers so much cleaner over my Monster gold-plated ethernet cabling [bhphotovideo.com], I can easily hear the difference. Just because you're bit-deaf doesn't mean that there isn't real benefit to the rest of us.
Moran.
Parent
Whatever saves time (Score:5, Interesting)
I've spent many hours debugging things that ended up being poor quality TP connectors, but I've also saved countless more hours producing them myself compared to running to the store everytime.
For any permanent installation, go for the molded cables. For anything thats temporary, just pick whatever cable is closest.
And you're not guaranteed to be free of problems just because you buy expensive stuff, I've had problems with Dell PowerEdge switches and factory-made, properly molded STP cables, the RJ45 plug was simply too small and the copper pins didnt connect every time. Really odd, we had to throw away a whole box of STP patch cables for that reason.
Create your own but TEST the cables... (Score:5, Informative)
I've learned the hard way when setting up a couple of clusters: You MUST use custom-made, cut to length cables to prevent a huge rats nets in the server room. Buying precut cables is a disaster. I had to rip out and completely rewire one cluster because I made that mistake.
However, you need to TEST the cables. And not just by plugging in and making sure it works, but a full ethernet validation tester.
I've been very happy with the Fluke Cable-IQ qualification tester [flukenetworks.com], which doesn't just make sure that the wiring is correct, but actually tests the cable up to gigabit speed to make sure everything is kosher.
Re:Create your own but TEST the cables... (Score:5, Informative)
This is the most sensible response so far.
The submitter neglected to mention how often this scenario is encountered though. If this happens frequently, buying a cable tester probably makes a lot of sense and will save a lot of money, time and headaches in the future.
However, if this happens very rarely, just buy the cable and be done with it.
Parent
Re:Create your own but TEST the cables... (Score:5, Informative)
And at $1,270.99, it's an absolute steal! [cdw.com]
Unless he's making hundreds/thousands of patch cables, I think the original poster is better off buying a commercially made cable.
Parent
Re:Create your own but TEST the cables... (Score:5, Interesting)
If you're testing to certify cat5, cat5e, or cat6 you need a cable tester. If you cannot certify the cable to a category you cannot guarantee the cable will work. So the cable is always suspect when you have connectivity issues.
Keep the OSI model in mind, errors at the physical layer cause the whole stack to collapse.
The advantage of cabling over wireless is that you can guarantee that the cable will work where there's no such promise with unlicensed RF spectrum.
Parent
He's right... (Score:5, Funny)
You can certainly screw it up if you do it yourself, for example you could forget the signal directional markings [denon.com] and then the signal would not know which way to go. Why do you think there are Ethernet cables at $500/1.5m? You think respectable companies are just trying to steal your money?
Don't cross the data streams! (Score:5, Interesting)
Pointy Haired Nitwitt (Score:5, Funny)
If the Belkin cable fails, you can blame Belkin (Score:5, Insightful)
Bad Attitude (Score:5, Insightful)
This principle of going with the provider you can sue over the one you can rely on is becoming far too prevalent.
I'm not saying that there's anything wrong with Belkin, and I think in this situation the pre-made cables are the better option.
However, in a more general sense, I'd prefer that my systems didn't go down rather than being able to point the finger when they do. If you are the front end provider of a service your customers are not going to be placated by the fact that, even though all their data is gone, you are currently seeking glorious retribution from the guy that solders the LEDs onto your motherboards (or whatever).
On top of this, when things go tits up at three o'clock in the morning - you can be sure the Belkin shop won't be open.
Parent
Re:If the Belkin cable fails, you can blame Belkin (Score:5, Insightful)
If something happens with the Belkin cable, you can blame Belkin.
That presumes:
Besides, do you really want to crimp your own cables?
Yeah, but I'm one of those crazy people who fix their own fences, hang their own ceiling fans, build treehouses for their kids, and generally like to do things not conducive to the strictly consumer lifestyle.
Parent
Rewiring our building (Score:5, Informative)
We had a contractor come in and rewire our facility. They ran raw CAT 6 and hand terminated it, then TDR'd each run.
Your boss is unclear on the tools needed and the difficulty...just simple hand crimpers were all they needed. There's going to be
an impedance bump at the RJ anyway...the cable's not twisted there.
As to making them yourself or buying patch cables? It's way cheaper to buy them (I like L-Com) but if you need one *right now*,
(or a custom length) it's cheap to have a crimp tool, some RJs and a roll of cable handy in the corner of the office.
Doubt he's correct, but believe him anyway! (Score:5, Insightful)
Wait a minute. Your boss is telling you to buy cables instead of toiling to make your own, and you're _complaining_? I don't think a self-terminated link of CAT6 will have the slightest trouble maintaining 20 megabits, but that's not the point.
Word of advice, take his word for him and nod. If he's willing to spend money to make your job easier, then keep that job!
Not worth the responsibility (Score:5, Insightful)
Your boss is a dumbass.. (Score:5, Interesting)
Ask him how the premise wiring in every commercial building in the world is installed. They order patch cables from some commercial patch cable vendor for every run, riiiiiiiight.
Also, CAT5e is fine for what you are doing. I agree with the previous poster that you could practically use tin cans and a string for this.
These special dies, jacks, and connectors are called "CAT5" parts and you can buy them at Home Depot I think. Does that make them "special" ?
Drill test (Score:5, Insightful)
Best advice I've ever heard on cabling:
If you have to drill holes to run it, make your own. If you don't buy it premade.
Second best advice:
Test it all. Even if it comes in a shrink wrap package.
Re:your boss sucks at making ethernet cables (Score:5, Insightful)
Obviously your boss isn't good at making cables. While if you lack the skill to do something like make cables with care you're going to have problems, there's no reason that you can't make your own cables and have them perform just as well as the ones made by a machine in a factory.
They can put it under the "Tech" section if they like, but this is really another disappointing Ask Slashdot. It's disappointing because too many of these have this format: "my boss at work wants me to do X, but I'd really rather do Y; what are the merits of X versus Y?" All of them need to be summarily rejected, with a polite e-mail sent to the submitter which says "within the bounds of the law, you need to do what your boss asks you to do whether or not you necessarily agree with it. If you cannot convince your boss to do otherwise, and this is a problem for you, perhaps you should consider working elsewhere."
The other disappointing category of Ask Slashdot-type submissions are those questions that are factual in nature and have only one correct (and rather well-known, easily researched) answer. Asking a large group with varying levels of expertise makes a lot of sense when there are multiple possible solutions to a problem and there is room to be creative. It makes no sense when it's more of a yes/no question -- remember the recent Ask Slashdot that asked whether spam is increased by trying to opt-out of spam e-mails? That's an excellent case in point, and not atypical either. That should have been an "Ask Google", not an "Ask Slashdot".
I think it's a shame that the quality of these particular submissions are on the decline. There's nothing inherently wrong with the "Ask Slashdot" format and there are a lot of very knowledgable people who browse this site. I'd love to see how creative they can be. It's just never going to be as good as it easily could be when it's handled this way.
Parent
Re:your boss sucks at making ethernet cables (Score:5, Insightful)
Bull! Entirely aside from what the submitter should do to protect their job, it is topical on slashdot to question whether DIY ethernet cables are any good, just as people on a home repair DIY site might discuss whether doing drywall yourself is worthwhile.
When the only answer slashdotters can imagine is "just pay somebody else to do it," that is the day there is no point reading here.
Parent
Re:your boss sucks at making ethernet cables (Score:5, Funny)
When the only answer slashdotters can imagine is "just pay somebody else to do it," that is the day there is no point reading here.
Hey, that was pretty good. What would you charge to make my posts for me?
Parent
Re:your boss sucks at making ethernet cables (Score:5, Insightful)
They can put it under the "Tech" section if they like, but this is really another disappointing Ask Slashdot. It's disappointing because too many of these have this format: "my boss at work wants me to do X, but I'd really rather do Y; what are the merits of X versus Y?" All of them need to be summarily rejected, with a polite e-mail sent to the submitter which says "within the bounds of the law, you need to do what your boss asks you to do whether or not you necessarily agree with it. If you cannot convince your boss to do otherwise, and this is a problem for you, perhaps you should consider working elsewhere."
I don't know about you, but I was hired for my technical expertise. It is part of my job description to let management know when they are making bad technical decisions. If they still insist after that, then sure, I gotta shrug my shoulders and do it; but until then, it's my job to find out the facts and make sure they stay informed...which is exactly what the questioner is doing.
Save the "shut up and do as you're told" bit for McDonald's burger-flippers. We're professionals here.
Parent
Re:I make my own all the time. (Score:5, Funny)
Seconded. I make all my own patch ca$lw7 and3@0 datt trd!@m34ssion ha*F aslwts bben3n vereryu reliabl3233e.
Parent
Re:Just do what your boss wants (Score:5, Insightful)
It's clearly not your company's core business to make their own patch cables. It may be fun for you to wittle down your own toothpics from lincoln logs but if it's not in your job description it ain't going to fly. Seriously, just buy the damn stuff and do what your boss has asked.
Exactly.
We buy all our patch cables in bulk. There's no reason for me to assemble a new cable every time we want to patch in another machine. It may not take long to throw together a 6' cable, but why waste any time at all? Break open a package and plug it in. Done.
We do keep a couple spools on hand, and some wiring tools. If we absolutely need a 15' cable and we don't have any on hand we'll throw one together...
Or if we really need a new wall jack somewhere... It's good to have the capability to do some of your own wiring if necessary... But for anything substantial we'll contract someone else to do that, too.
But, really, that isn't what I'm paid to do.
Parent