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Handmade vs. Commercially Produced Ethernet Cables 837

Posted by CmdrTaco
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?"
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Handmade vs. Commercially Produced Ethernet Cables

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  • by linzeal (197905) on Monday April 27, 2009 @09:38AM (#27728979) Homepage Journal
    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.
    • by Just Some Guy (3352) <kirk+slashdot@strauser.com> on Monday April 27, 2009 @09:48AM (#27729135) Homepage Journal

      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.

      • by jcr (53032) <jcr@nOspAm.mac.com> on Monday April 27, 2009 @09:56AM (#27729255) Journal

        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

        • 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!

          • by Forge (2456) <kevinforge&gmail,com> on Monday April 27, 2009 @10:43AM (#27729943) Homepage Journal
            There are 3 types of Ethernet cable.

            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.
            • by camperdave (969942) on Monday April 27, 2009 @10:49AM (#27730031) Journal
              Set up a dummy company, and get them to sell you the $300 cables for $250. Then crimp the cables and sell them to yourself. You pocket $250 less materials, the boss gets his "professionally made" cables, and everybody is happy.
            • by Glonoinha (587375) on Monday April 27, 2009 @10:55AM (#27730129) Journal

              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.

              • by daveywest (937112) on Monday April 27, 2009 @11:58AM (#27731267)

                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.

                ... or hire an unpaid summer intern from a local high school who wants some experience in the IT biz. Lets be honest here. Its people can't find jobs right now, and if the kids is even remotely interested in IT, he will choose pulling cable through your dusty attic over flipping burgers any day.

              • by Jeff DeMaagd (2015) on Monday April 27, 2009 @12:47PM (#27732141) Homepage Journal

                The real acid test would be to get one of these TDR units, buy 10 cables from each of two or three reputable companies and compare it to the results from 10 cables done in-house.

                All this talk without an objective stress test is pretty pointless.

              • by adolf (21054) <flodadolf@gmail.com> on Monday April 27, 2009 @01:53PM (#27733207) Journal

                My opinion is a little different: Don't build them one at a time. And don't buy them one at a time, either.

                Just pick up a bunch of different lengths of pre-terminated cable from the good folks at deep-surplus.com. Buy a bunch of 1-foot cables, along with some 3-foot cables. 5-foot cables. 7-foot cables. 12-foot cables. So on, so forth. Then, when you need a cable of a given length, you've (gasp!) already got one!

                They're easy to use, too! Just reach up on the shelf, and get one! Way faster than finding the strippers, the cutters, the crimpers, the box of ends, and the box of wire... And then you've still got to cut, strip, sort, cut, insert, and crimp the shit together, before doing the same thing on the other end.

                Feh.

                They cables from deep-surplus cheap, they're Chinese, they're durable, consistent[1], and I have never had a bad cable after years of doing this whenever possible. Plus, every order comes with a bag of Skittles.

                The trick to making this economical and time-efficient is to put it all on one PO.

                [1]: Speaking of consistency: I do have the occasional cable that I make myself go wonky, in applications where prefab cabling doesn't apply, like UV-rated Cat5 up a radio tower. This, despite using a good crimper with a good die, and high-quality ends which are made specifically for the wire in question, and a lot of practice to develop decent workmanship. The Chinese cables are consistently more consistent, and always work.

              • by kiyoshigawa (844575) on Monday April 27, 2009 @02:09PM (#27733499)

                Orange and white, Orange. Green and White, Blue. Blue and White, Green. Brown and White, Brown.

                Just Remember: OverWeight Olga Gives Willingly, But Betty White Gives Bitchin'-Wild Blowjobs.

              • by jemenake (595948) on Monday April 27, 2009 @04:24PM (#27735881)
                And here's another tip when making several cables at once...

                Make one long cable of the total length of all of the cables you want, and terminate the two ends and test the cable. Then, you know those two ends are good. Then, for your first "finished" cable, snip off the length you want, and terminate the snipped end. Then, test the cable. If it fails, you know which end needs fixing.

                Then, with the remaining slightly-less-long cable, terminate the snipped end of that, and test. Then, snip off the next length you need, etc...

                I used to just pull off the length I needed from a spool, crimp the two ends, and test. But, if the cable failed the test, and I couldn't see where the problem was, I'd have to flip a coin to decide which end to re-do first. The above method avoids the coin flip. You'll know which end you have to re-do.
            • by ProfessionalCookie (673314) on Monday April 27, 2009 @12:38PM (#27732005) Journal
              Hint: The injection molded ones are made by robots.
        • Re: (Score:3, Informative)

          by MikeBabcock (65886)

          I never ever make my own cables for long-term PC connection patch cables, only for patch panelswitch connections and cross-overs.

          I wired all of my own in-wall cabling at home, but I pay others to do it for work (just for time reasons).

          I always use packaged stranded copper patch cables for connecting PCs to wall jacks though, as they're more flexible and resilient to breakage when twisted or bent repeatedly. Solid core cables will snap or degrade rapidly if bent repeatedly or at sharp angles.

        • Re: (Score:3, Funny)

          um... the commercially cut cables are made of certain length for a reason. 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, or even worse, cross talk. This happens to twisted pair as well as coaxial due to energy absorption of the copper cable themselves (part of the energy in the inner cable gets converted to heat for coax and heat conversion not equalizing for twisted pair, emf wi

          • by ACorvus (202386) on Monday April 27, 2009 @10:39AM (#27729885) Homepage

            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.

          • by thebes (663586) on Monday April 27, 2009 @10:40AM (#27729905)

            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.

          • Re: (Score:3, Informative)

            by gambino21 (809810)
            Why is this modded interesting? I thought the parent was trying to be funny. Somehow I doubt EMF harmonics has anything to do with the nice round values like 6 and 10 ft, that are commonly found at compusa, best buy, etc
          • Not as such... (Score:5, Insightful)

            by Anonymous Coward on Monday April 27, 2009 @10:59AM (#27730175)

            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.

          • by MarkGriz (520778) on Monday April 27, 2009 @11:13AM (#27730403)

            "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?

          • by DahGhostfacedFiddlah (470393) on Monday April 27, 2009 @11:22AM (#27730581) Homepage

            See, this is exactly why I adore /. Name one other popular site where you'd get ten bites on a troll that 99% of the population doesn't even understand.

            Right down to the Where is the "Ignorant" mod tag? signature. 10/10 for you, sir.

          • by Aceticon (140883) on Monday April 27, 2009 @11:45AM (#27731029)

            Mod parent up!

            I'm an EE (non-practicing) and he's right. This is even worse with twisted pair 'cause the EM emissions come out all twisted and curvy and can cause serious interference with other cables.

            It's also important to always cut your cable in multiples of 30 cm if you're going to use Gigabyte Ethernet to make sure your wave always gets to the other side in phase - you don't want a phase mismatch to happen.

            Don't forget to terminate everything - i can tell you that the actual speed of a cable where one of the sides is neither connected to anything nor properly terminated is ZERO bps.

            Last but not least, always make sure that both sides of the connection send equal amounts of data so that the cable doesn't get a transmission fatigue problem due to the electrons always going in the same direction.

            Here you have it, the secrets of professional cable making and usage at your fingertips: don't waste them!!!

      • by exploder (196936) on Monday April 27, 2009 @10:39AM (#27729883) Homepage

        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.

        • by halber_mensch (851834) on Monday April 27, 2009 @11:32AM (#27730765)

          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.

          I absolutely agree. You can't trust an IT professional's "homemade" cables any more than you can trust a cook's "homemade" meal. That's why you should always buy your work instead of doing it yourself. I went to Outback Steakhouse yesterday and ate the best steak I ever had, and do you know why? It was because THEIR COOKS DIDN'T MAKE IT! They did the sensible thing and took my order across the street to McDonald's, returning to me (at a marginal reseller's markup) a quality steak from a trusted manufacturer. And if the steak had been bad, the cooks had done their duty to their job security and could just say to their boss, "Hey, it came from McDonald's! And I'm a valued employee that has skills you need, like being able to run across a busy street during a dinner rush and buy something from another company! So you should definitely just blame McDonald's and let me get back to flirting with the hostess!" Bingo! The boss is happy, the customer gets mediocre service and quality at insane profit, and the cooks don't have any value to the business at all! That's exactly how every business should operate! Because if you trust your workers to do the jobs you hired them for, you're just setting yourself up for disappointment. Because since you weren't able to purchase your employees at an employee store and instead had to choose them yourself, they obviously must be as unqualified for their jobs as you know you are.

      • Re: (Score:3, Interesting)

        by mrops (927562)

        I second that.

        Drive to Best Buy: 15 Min
        Time to purchase: 10 Min
        Drive back home: 15 Min
        Cost of cable: $45 (ball park)

        vs

        Pull cable to desired length: 30 seconds
        Crimp end 1: 1 min
        Crimp end 2: 1 min
        Cost of raw material: $5 (ball park)

        So Unless you make about 40$ in 2 min i.e. 1200$ an hour, its better to crimp your own.

    • by Z00L00K (682162) on Monday April 27, 2009 @10:09AM (#27729423) Homepage

      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.

  • Always buy them (Score:5, Interesting)

    by igb (28052) on Monday April 27, 2009 @09:38AM (#27728983)
    We have TDR equipment and appropriate tools, but we still buy patch cables in bulk. We tested an assortment of ones we had made with cheap crimping tools, and they were all horrible. We can make decent ones, but it takes longer and costs more than buying them pre-tested.
    • Re: (Score:3, Informative)

      by seanadams.com (463190) *

      Aren't the commercial ones also hand made? I find it hard to imagine an automated way of doing it.

      Commercial cables have going for them: rubber injection/overmold for more ruggedness, and they're pre-tested. Aside from that, I don't see exactly what should stop you from making decent ones yourself, assuming sufficient skill.

    • Agreed. (Score:5, Informative)

      by dr_wheel (671305) on Monday April 27, 2009 @09:57AM (#27729269)

      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.

  • by polle404 (727386) on Monday April 27, 2009 @09:38AM (#27728993)
    Monster cables, dude, Monster cables...
  • by khasim (1285) <brandioch.conner@gmail.com> on Monday April 27, 2009 @09:39AM (#27729001)

    And I have never had any problem with them. Even on 50 servers running at full Gig. No errors.

  • Whatever saves time (Score:5, Interesting)

    by boaworm (180781) <boaworm@gmail.com> on Monday April 27, 2009 @09:39AM (#27729011) Homepage Journal

    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.

    • Re: (Score:3, Insightful)

      by CrazedSanity (872448)

      The problem with the "grab whatever if it's temporary" is that temporary solutions oftentimes become more permanent than anything. I have had many experiences where fixing a problem in the server room exposes some "temporary" fix from years ago that I never had time to make permanent (and since it worked, nobody thought twice about the problem it had fixed).

      Or when developing web applications, somebody implements that "quick function" that does X, intended only for internal stuff. Another feature comes al

  • by Enry (630) <enryNO@SPAMwayga.net> on Monday April 27, 2009 @09:39AM (#27729013) Journal

    but makes perfectly fine cables from what I saw. I generally don't do it anymore unless I have a very custom length as pre-made are really inexpensive and over 10 cables I usually have to re-crimp at least one end. Does your boss have any proof that hand-made cables are inferior?

  • by nweaver (113078) on Monday April 27, 2009 @09:40AM (#27729017) Homepage

    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.

  • by Ecuador (740021) on Monday April 27, 2009 @09:41AM (#27729033) Homepage

    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?

  • Bite the bullet (Score:4, Informative)

    by bernywork (57298) <bstapletonNO@SPAMgmail.com> on Monday April 27, 2009 @09:42AM (#27729041) Journal

    I buy cables because I would go through 5 - 10 cables a day and by the time I made them, tested them, labelled them, I could be doing 101 other things.

    It's not to say that you can't do it, you can. It's just a matter that the amount of time you spend doing it just makes it a hell of a lot cheaper in the long run to buy them.

    This is ESPECIALLY true when dealing with CAT7 or STP. On a 20Mb line (Probably a 100Mb link) the chances of having a problem though are pretty low provided you terminate it cleanly.

  • by mc1138 (718275) on Monday April 27, 2009 @09:43AM (#27729049) Homepage
    I took a network troubleshooting class in college, and we had to test the integrity of data runs that we pulled ourselves and if they weren't good enough we had to do them again till we got our numbers down. I'm sure there are hundreds of data companies that would disagree with you on what it takes to make quality cables and I'm sure "expensive dies" and other nonsense like that really don't help that much when it comes to quality. All you need is a steady hand and lots of practice.
  • by nefus (952656) on Monday April 27, 2009 @09:43AM (#27729059)
    I think you have a pointy haired boss who can't do anything himself. Thats why he has other people do the IT. I've run into these types of people before. He's probably the kind of guy that staples the crap out of cat cable and wonders why his network is down.
  • by Glass Goldfish (1492293) on Monday April 27, 2009 @09:46AM (#27729101)
    Why put your neck on the line? If you make a cable and anything goes wrong, even if it happens later on, you're blamed. If something happens with the Belkin cable, you can blame Belkin. Even if it isn't Belkin's fault. Especially after your boss has told you to do something. Whenever you go up against an authority figure, the best you can hope for is proving them wrong. It's better to say "What a great idea boss!" and buy the cable. If it works, great. If it doesn't work, don't rub it in. Besides, do you really want to crimp your own cables?
    • Bad Attitude (Score:5, Insightful)

      by PinkyDead (862370) on Monday April 27, 2009 @10:31AM (#27729763) Journal

      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.

    • If something happens with the Belkin cable, you can blame Belkin.

      That presumes:

      1. You make crappy cables.
      2. Your boss is watching over your shoulder to see whether it's a homemade or bought cable.
      3. All of your bought cables are labeled by the manufacturer.
      4. Your boss cares beyond "is it fixed yet?"

      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.

  • by Peter Simpson (112887) on Monday April 27, 2009 @09:46AM (#27729103)

    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.

  • 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!

  • by hhaarrvv (1521241) on Monday April 27, 2009 @09:51AM (#27729185)
    Your cables would be fine, but if ANYTHING ever goes wrong the first thing your boss will say is "It's probably that damn cable you made when I told you to buy one." It's just not worth it.
  • by ockers (7928) on Monday April 27, 2009 @09:53AM (#27729209) Homepage

    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" ?

  • by jollyreaper (513215) on Monday April 27, 2009 @09:54AM (#27729213)

    It really preserves the assonitic complexity and quality of the packets when they move from your wall to your router. Cheaper cables let noisy bits through that go all wobbly and clog your connection. I hear their new wifi cables are hella expensive but totally worth it.

  • by pz (113803) on Monday April 27, 2009 @10:04AM (#27729371) Journal

    I've bought thousands of dollars of cable. Full disclosure, it has been BNC cable, and not ethernet, but I think my experience is likely germane. This cable has been used to construct installations of scientific equipment that gets reconfigured pretty frequently (and I've been the primary user on most of this equipment). I have never, ever had a single cable-related failure using ITT/Pomona cables. My peers, on the other hand, use hand-made cables and are constantly debugging their setups.

    I spend my time doing my job (collecting data), while other people in my lab spend their time fixing problems. (Really full disclosure, I'm the only one with an EE degree.)

    Good cables can be found inexpensively. These are the ones you want. Cheap cables can be found for less money, but these are the ones you do not want. Custom cables, unless you have high-quality crimping tools (the $39.99 variety don't cut it) and a proper means for doing testing, which means TDR and bandwidth testing in your case, just are not worth it for general-purpose use.

    Look at it this way: how long does it take you to generate a qualified cable? Not how long does it take you to make one cable, but how long does it take you to make one cable that you will use, including all of the failed crimps, cables that were cut too short, too long, were miswired, or must be discarded, for some other reason. How many cables will you be making? Total that up and use 1/2 of the time to search for low prices on high-quality cable instead. You will be ahead in the end.

  • by pecosdave (536896) * on Monday April 27, 2009 @10:10AM (#27729437) Homepage Journal

    with equipment that's not much different than stock equipment. I test these cables with a DTX-1800, they do great.

    They're sticklers for BlackBox brand cable, I don't know if it's because the cables good, or the more likely scenario that instead of specifying TIA-568B compliant cable they have have to give a part number to make a "Typical". A "Typical" is a blue print for a cable. Remember, it's government, loads of red tape.

    We also use Black Box brand connectors, again, for part number reasons I'm almost certain. For the Cat-5 stuff there is something a bit different than your run of the mill cables, it's the inclusion of black load bars that get crimped into the connection. A bit different than most connectors I've used.

    The only Cat-6 I've made was a specialized connector with additional grounding added, so I wont get into that.

    Beyond what's mentioned the only difference between NASA and the rest of the world is the use of really expensive test equipment, and the insistence that calibrated ratcheting crimpers are used. For test reasons I've made cables using my own stuff and put it on the Fluke, I hate to say it, but my uncalibrated out of the box $20 crimpers from Ideal do just as well as there $150 at minimum crimpers that are custom pieced together. At least according to the Fluke.

  • by ddillman (267710) <.dgdillman. .at. .gmail.com.> on Monday April 27, 2009 @10:12AM (#27729465) Journal
    I've personally crimped thousands of patch cables and other ethernet lines in Cat5 and Cat5e. However, it's been my understanding that it is nigh impossible to field crimp Cat6 to meet specs. That may have changed, since the last time I asked was a couple of years ago. Cat5 and 5e are relatively easy, and as others mentioned, making your own eliminates messy loops of extra cable hanging about. And there's some satisfaction from making your own stuff as well. But Cat6? As others mentioned, it's probably cheaper and better in the long run to purchase ready-made cables from a reputable source.
  • Be Careful! (Score:3, Informative)

    by tignet (1303483) on Monday April 27, 2009 @10:24AM (#27729647)
    There are two types of cable, stranded and solid core. Solid core is generally used for the horizontal cabling (from the patch panel to the jack at the user area), where stranded is used for the patch cables.

    Solid core has slightly better propagation properties (the 100M limit implies solid core for example) however it also acts similar to a wire coat-hanger. Like any metal it weakens as it bends and after a period of time it'll grow weak, thin and even completely break.

    Stranded is similar to a braided rope, it can withstand constant reconnections (user area, especially common with laptops), movements (telcom closets when you're moving the cable mess to access equipment ports) and the stress that will wear down the solid-core cables.

    Do yourself a favor and make sure that if you create your own patch cables:
    • Cable correctly. Know your color code, it makes future changes (such as to length) MUCH easier and the standards are in place for a reason. Ethernet uses pins 1, 2, 3, and 6 -- which match up exactly with the standard pinouts. Making your own pinout from left to right for example will not allow for cross-talk cancellation and will cause performance problems. Generally you want to match whatever standard your patch panel is, probably 568-B.
    • Use stranded cable. It's more difficult to work with (it doesn't stay in place like solid core, making it more difficult to put the ends on) but you definitely want to do this.
    • Use RJ45 connectors intended for stranded cable.

    There's nothing wrong with making your own patch cables, and it could potentially save you big bucks (compared with buying a $35 patch cable at a local store). However if it's not done right you will kick yourself down the road -- or more likely blame the network electronics, server, network cards, or whatever you normally blame. :)

  • Drill test (Score:5, Insightful)

    by salesgeek (263995) on Monday April 27, 2009 @10:25AM (#27729667) Homepage

    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.

  • Funny (Score:3, Informative)

    by kimvette (919543) on Monday April 27, 2009 @11:27AM (#27730663) Homepage Journal

    That's funny.

    I mean, a couple of weeks ago I finished up a job where I went into a mess, with a mix of premade cables and mixing A and B pinouts. I re-did most of the connections - by hand - and installed all new patch cables - made by hand, and tested every link with a TDR. A couple failed - turned out the oh-so-slight crosstalk between T568B patch cables and the old T568R runs was just enough to break the link so I switched those old connections to T568B and all was well.

    I've seen articles which claim the crosstalk from mixing A and B only sometimes cause link problems, but I've seen it often enough to make it a blanket rule to always, always, always go 568B. 568B is supposedly deprecated but every cable I've ever bought off the shelf, aside from crossover cable, has been wired 568B so I always stick with B.

    Most of the premade patch cables that were on site tested bad BTW. I've since installed a few premade cables but they were brand new and those tested fine.

    If you're going room to room, don't go with premade patch cables. Get a spool of CAT-6 and use keystones (jacks) on the PC side and a patch panel (or keystones if the boss is too cheap - although once you do more than 20 jacks the patch panel becomes much cheaper so just tell him to STFU and do it right, and skip one appetizer and alcoholic beverage at a meal to recoup the cost) on the other side. Just hanging a patch cable out of the wall is really hack. It works, but it's fugly.

To thine own self be true. (If not that, at least make some money.)

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