"Most of us, if we do not deal in high-speed digital signalling, have a kind of "DC Circuits" understanding of wiring where the most important thing is simply that the wires connect the right points together."
An example of this is thinking that the order of wires in your crimps doesn't matter so long as it is consistent at both ends. This is emphatically not the case! Each twisted pair in a cat5 cable is intended to carry a signal and it's inverse. If you add a signal to it's inverse you should get nothing, but if noise has skewed both signal and inverse, the result of addition will be the isolated interference you need to subtract from your signal. Cat5 connections rely on this noise cancellation to work, as the wires used have little or no shielding. If you put wires into the wrong order so that signals are not paired with their inverses, this noise cancellation system is totally fubar'd and will likely make things worse than if there was no noise cancellation at all. It might work over a few meters, but longer cables are almost guaranteed to fail.
Pick a wiring standard (568-A or 568-B) and stick to it. If you do this, it's pretty hard to mess up anything else so badly that your cables won't work. Bluejeanscables is a cable manufacturer, so they're probably exaggerating how hard it is to make a good cable. In particular, their "buy american" schtick is not very applicable to cabling. Monoprice is functionally equivalent, even if it's from China.
Note: If you're wiring your home, be sure to use plenum grade cable. Other cables may be flammable and fire codes tend to disapprove of having flammable cords running through your home.
Also Note: I am not an electrician. I just found out the hard way by making bad cables for my home. If you buy one $50 spool of cable, $5 of terminations, and a $20 crimp tool you'll never have to pay for network cables again. I'm not sure if it would be worth it now, but it certainly was 10 years ago!
I'm not an electrician but have installed around 10 million feet of low voltage wire under one in a previous job.
Plenum cabling is typically only required when the cabling is in a space open to the air (e.g., a t-bar grid ceiling with HVAC cold air returns in it). If sealed behind sheetrock or something else you can use the standard stuff, which is less expensive.
Also, almost as important as the proper ordering of the individual strands is preserving as much as the twisting as possible. Hard kinks in the wire and stripping too much at the termination ends can affect that.
Running too near other wiring can severely affect the noise as well. If you need to cross it, perpendicular is the best.
And lastly, be aware of the maximum rated length for the wiring when doing long runs. It can only reliably carry the signal so far.
> Bluejeanscables is a cable manufacturer, so they're probably exaggerating how hard it is to make a good cable. In particular, their "buy american" schtick is not very applicable to cabling. Monoprice is functionally equivalent, even if it's from China.
This. The article has some very decent and scientifically valid advice regarding terminations, and they unnecessarily throw in this protectionist voodoo about Chinese cable being "almost always terrible" (with an American jobs reference to boot), without backing up their assertions with tests of cables. This makes me somewhat mistrustful of the rest of their article, for no good reason.
So, given the context they may have actual conclusions they reached about Chinese made cables.*
I have had alot of experience in the recent few years with Chinese made wire, and I am unsurprised when it comes out bad. The most common issue I have had is buying a particular gauge and getting something smaller, but marked as the gauge I'm expecting, ex: buying 22awg and getting 24awg.
I don't have much recent experience with network cables being bad, mainly because I only use cables from 3 manufacturers (Belkin, Carlisle Interconnect and Ortronics). But my takeaway from the world of patchcables is that alot are more flakey than people really notice.
* The problem with the phrase "Chinese made" and its like is that between two things made in China you might see wildly different quality. The real thing that drives how well something is made is the quality standards the goods are expected to meet. Typically the case with bad Chinese made goods is that the quality was not met, either it was not expected, it was not tested or not enough pressure was put on the manufacturer to meet the standards.
What the previous test BJC did mainly reveals is that cables are not being tested to meet the standards they are expected to meet. A number of factors are probably contributing to this, such as the industry not really caring to test cables and the price points driving down QA expectations.
To add to the whole Chinese made issue is that factory scrap and seconds is often resold as product. This is stuff that failed QA and should have been torn down to be disposed of but is instead either sold as is or refurbished on a second shift.
I work as an electrical engineer on military aircraft.
High speed cabling is susceptible to all sorts of nasty "gremlins". I work with copper fibre channel runs, RF and long 1394 runs regularly. I am still preaching the gospel to other technicians and engineers that ringing this cabling out with a multimeter is NOT enough to guarantee that the signaling will get through! This article is the perfect demonstration of this. Those terminations would have rung through using a multimeter, which is just sending a very tiny DC signal, but the TDR analysis showed poor terminations. I have encountered the exact same scenario in my own work.
I worked as an intern at a company installing (then) 100BaseT and FDDI cabling in industrial installations and also office buildings 20 years ago. For every network socket installed, the customer got the (thermal-paper-)printout of a network cable tester.
I'd expect this to be the minimum level of diligence when installing cables on a military aircraft, or shouldn't I? ;-)
I had no idea there were even 2 wiring standards. Only found out last year when trying to connect via an older cat5 cable that was going from my garage to the office at my house.
And after reading your comment also realized it is probablhy not up to code as well...
You actually require both wiring standards to create a cross-over cable.
The tricky bit I've found (and I also used a Fluke tester on all cables I manually terminated) is that when terminating cat-6 cables, the inner two pairs had to be separated and terminated perfectly symmetrically. With cat-5, or 5e, you seem to be able to get away with some sloppiness, but with cat-6 you need to think like a seamstress. Those wires need to be exactly in place, and exactly the right length.
I used to find cable termination quite a zen-like experience. I'd do a hundred cable terminations, then fifty cable tests, and very rarely get to smile at a perfect result.
Wait. I didn't know this. They send inverse signals? Really? Does that mean that long cat-5 cables made with the wrong standard wont work on some equipment?!
You are mentioning two things. 1) yes, they send send signals, and their "inverse" over a pair of cables. That's guaranteed by the use of transformers on your network card/network switch. Current that the transformer sends in one line of a pair, has to be returned in the other pair.
On an old 10MBit or 100MBit/s card (10BaseT, 100BaseT) on each device there will be one pair to send data out, and one to receive data. This uses up 4 pins on your RJ45 connector, the other 2 are unused. The pair that is used on your network card to send out data are pins 1 and 2. The pair that is used on your network card to receive data is on pins 3 and 6.
The 2nd thing you mention are the two standards TIA/EIA-568 assigns colors to pins, and they have a version A and B where the colours of pair 1/2 and pair 3/6 are swapped.
Hence, when you have a cable where one side is wired according to "A" and the other is wired according to "B" you have something that, in the old days, was called a cross-cable, which you could use to directly connecto two computers with each other, without having a hub or switch in between. Which is very useful, especially if you'd connect e.g. two switches in two buildings with each other.
But because miswirings regarding the two color schemes were so frequent, and connecting routers/switches/computers directly using "straight" cables was so convenient, most devices manufactured after the 90s can swap these pairs internally automatically. Hence no matter if you have a strait or cross-cable, or a miswired 568A/B installation computers will just function fine.
With 1000BaseT (Gigabit-Ethernet) data is transmitted and received on all pairs simultaneously, and also this miswiring is automatically detected and taken into account.
There are two standards, you can pick either it doesn't matter. You use the same pattern of colors on both sides. (The colors different between the standards, but the difference is cosmetic, not electrical.)
That means pin 1 is the same on both sides, the devices using this cable have to be different, like a network card on one side and a switch on the other. Internally the two devices have opposite meaning of what wire is receive and transmit.
Or you can use one standard on one end, and the other standard on the other. This makes a crossover cable, where the receive and transmit pairs are swapped.
This is good when connecting two devices that both have the same belief about which pin is receive and transmit.
These days people got tired of dealing with that and most devices auto negotiate which pin is which, and the type of cable doesn't matter.
Ethernet uses differential signaling, a pair of wires transmits the positive and negative sides of the signal. When interference hits the twisted pair, it affects both signals the same way, and the effect is cancelled out.
If you try to use two wires from different pairs for one signal, you lose this property because now the wires are further apart, and possibly worse, twisted with another signal.
An example of this is thinking that the order of wires in your crimps doesn't matter so long as it is consistent at both ends. This is emphatically not the case! Each twisted pair in a cat5 cable is intended to carry a signal and it's inverse. If you add a signal to it's inverse you should get nothing, but if noise has skewed both signal and inverse, the result of addition will be the isolated interference you need to subtract from your signal. Cat5 connections rely on this noise cancellation to work, as the wires used have little or no shielding. If you put wires into the wrong order so that signals are not paired with their inverses, this noise cancellation system is totally fubar'd and will likely make things worse than if there was no noise cancellation at all. It might work over a few meters, but longer cables are almost guaranteed to fail.
Pick a wiring standard (568-A or 568-B) and stick to it. If you do this, it's pretty hard to mess up anything else so badly that your cables won't work. Bluejeanscables is a cable manufacturer, so they're probably exaggerating how hard it is to make a good cable. In particular, their "buy american" schtick is not very applicable to cabling. Monoprice is functionally equivalent, even if it's from China.
Note: If you're wiring your home, be sure to use plenum grade cable. Other cables may be flammable and fire codes tend to disapprove of having flammable cords running through your home.
Also Note: I am not an electrician. I just found out the hard way by making bad cables for my home. If you buy one $50 spool of cable, $5 of terminations, and a $20 crimp tool you'll never have to pay for network cables again. I'm not sure if it would be worth it now, but it certainly was 10 years ago!