“Why is Ethernet wire twisted inside?” is a subject that IT professionals and cabling experts are frequently asked. This riddle is around the operation of Ethernet cable and why it is referred to as balanced twisted pair. Let us unravel this riddle and discover the truth!
How do the twisted wires work?
The twists’ principal function is to reduce internal electrical interference. In effect, Ethernet cable has its own “shielding” built in. You may believe that unshielded Ethernet cable has no shielding and that protected Ethernet cable has shielding. This is just partly true. While shielded Ethernet cable, such as F/UTP has an overall foil shield, the cable cannot function without the “built-in” shielding of twisted pairs.
The purpose of the external, general foil shield is to keep outside electricity (magnetic fields or radio waves) from getting into your cable.
Every wire conductor produces an uneven electromagnetic field. As a result, one conductor may interfere with another. Given that gigabit Ethernet uses all eight conductors, this would be a terrible disaster if all the conductors began “talking” to each other. Cross-talk occurs when electrons are passed back and forth between conductors.
There will be a magnetic field encompassing every extension cable or anything that passes electrons through it to some degree. The magnetic field becomes smaller as the voltage decreases. The voltage in the Ethernet cable is relatively low, but it is still present, and the twists in the conductor pairs protect the cable from itself.
Each twist reverses the polarity of the conductors, canceling out disparities in their unique electromagnetic fields. As a result, electromagnetic equilibrium is achieved, which is why Ethernet cable is referred to as balanced twisted pair. We have achieved harmony. The couple is “quieter,” similar to a library. We can now converse with each other and genuinely understand each other.
What are the Reasons for Twisted Wires?
The Reduction of Noise
No engineer would tamper with equipment unless there was a benefit to doing so. The colorful wires are not twisted to make the conductor look odd; they are twisted to reduce unwanted noise signals.
Previously, telephone wires were not as elaborately or widely twisted as they are now. The pair of wires carrying or receiving telephonic signals would be twisted or their places on each pole would be switched. These poles were spaced at equal intervals and piled for several kilometers. The pole, now a relic from a brilliant era of scientific discoveries and advancements that saw the birth of what is now called “premodern” or even “modern” technology, can still be seen in rural areas.
The impulses sent over the two cables were of similar magnitude but polarity. As a result, if one wire carries a voltage +A signal, the wire parallel to it will carry a voltage -A signal. These are known as differential signals because the output of a receiver when they are received is the arithmetic difference of these signals. To generate 2A, the receiver subtracts A and -A. But why is this so clever?
Only in an ideal world would the receiver receive both signals A and -A without any noise. The environment will inevitably introduce noise into the cables, causing the signals to be corrupted. Noise signals, on the other hand, are injected without any polarity reversal: the source of noise induces a voltage component in both lines, say, +N, rather than +N and -N. As a result, the distorted signals received by the receiver are (A+N) and (N-A). However, because it subtracts both inputs, the resulting output is completely noise-free, as (A+N) – (N-A) = 2A.
However, it is based on a fallacy. It is based on the assumption that the amplitude of the noise created in the two parallel lines is equal. This is undoubtedly false, because the source may not be equidistant from the two cables. As a result, one wire would be subjected to more noise than the other.
One solution is to expose the other wire to additional noise, so making the two components equal. The magnitude of noise created in the two wires would be the same if they were regularly exposed to the source of noise turn after turn. This may be accomplished by twisting or swapping the wires!
Electromagnetic Interference (EMI)
Wires are no longer thick and taut between tall poles; instead, they are incredibly thin and commonly found taut or spreading between small, weirdly shaped boxes a century later. And, yeah, boxes and wires are connecting them all over the place.
The issue presented by so many closely spaced wires is that noise in a wire is now created not only by the environment but also by other wires in its vicinity. Electrons in motion, like those that make up a current in a conductor, emit electromagnetic waves. Electrons in the wire next to it can be disturbed by electromagnetic waves produced by one wire. Because EM waves are made up of oscillating or changing magnetic fields, an EM wave passing through a wire can generate a current in it. This is known as cross-talk, and the noise is known as electromagnetic interference (EMI).
Extensive braiding eliminates noise in two ways: first, as previously stated, equal exposure to the source ensures that most of the noise is canceled when the signals are subtracted by the receiver; and second, at each twist, the magnetic field produced by the wire changes its polarity, such that the currents induced are opposite in polarity, which eventually negate each other to produce effectively noise-free signals. Effectively, but not entirely!
Author: TechBlonHub
As a passionate blogger, I'm thrilled to share my expertise, insights, and enthusiasm with you. I believe that technical knowledge should be shared, not hoarded. That's why I take the time to craft detailed, well-researched content that's easy to follow, even for non-tech. I love hearing from you, answering your questions, and learning from your experiences. Your feedback helps me create content that's tailored to your needs and interests
