What is twisted pair cable in computer network | Twisted pair network connectors | Full Explained
Hello, I’m Sourav Khanna. And welcome to Network cabling part 1. Today we’re going to be talking about twisted pair network cabling. Then we’re going to talk about twisted pair network connectors. And then we will conclude with categories of twisted pair. I have a whole lot of information to cover and I need to get through this quickly. So let’s go ahead and begin the session. And we’ll begin by talking about twisted pair network cabling.
Twisted pair cables
Most people are familiar with twisted-pair cables because they are the standard in the modern LAN they are what you see most often when you’re looking at network cables. twisted pair cables are composed of four pairs of wires contained within an insulating sheath. Each pair of wires is twisted together to reduce electromagnetic interference, which is called EMI. The twist rates differ between the pairs to reduce cross-talk, which is a type of EMI.
The colors of the pairs of wires are always white, orange, orange, white, blue, blue, white, green, green, and white brown, brown. Twisted pair network cabling comes in either unshielded or shielded twisted pair that would be UTP or STP. The difference is that STP has an additional shield that is either wrapped around each pair of wires are around all four pairs of wires.
That shielding reduces the opportunity for EMI or cross talk, but it is more expensive and a little harder to work with. Because it’s not as flexible UTP or unshielded twisted pair is deployed in the network much more often than STP. There are also plenum and non-plenum types of twisted pairs. Most twisted pair cabling is non-plenum grade, but building codes usually call for plenum grade cable to be run in plenum spaces.
No, a plenum space is that area that is designed to assist in the airflow of a building for HVDC purposes, and most often, the planet Is that space between the false ceiling and the actual ceiling. Plenum cable is jacketed in either a fire retardant cover or in a low smoke PVC jacket. Plenum cables often have a polymer or nylon strand woven into the cabling or into the jacket to help take the weight of hanging cables.
This reduces the chance for the cable to stretch which can cause the pair or pairs of wires inside the jacket to break. The twisted pair is usually either a straight-through cable or a crossover cable, but it can also be used to create a rollover or console cable. A straight-through cable is used to connect different types of devices together, as in a computer to a switch or switch to a router.
Well, a crossover cable is used to connect similar devices together, as in a PC to a PC or a switch to a switch the straight through in crossover cable use different pinouts to achieve their connections. A rollover or console cable is often required to connect to the console port on a switch or a router. It is quite common for one end of the rollover cable to use an RJ 45 connector, while the other end utilizes an RS 232, also called a DB nine connector.
So now that I’ve mentioned those connectors, let’s go on to twisted pair network connectors. And we’re going, to begin with, the RJ 11. You don’t see these very much in what we think of as networking, but you do see them all the time.
The RJ 11 uses the sixth position for a contact modular connector. That’s a six p four c modular connector. It can carry data or voice and its common usage is voice communication, telephony, all of your telephone jacks are our j elevens.
Then there’s the RJ 45. This is the one that we always think about when we think about networking with twisted pair of cabling. It uses an eight-position eight contact or eight p eight c modular connector. It can carry data or voice and its common usage is data networking, Ethernet, then there’s the RJ 48 C, it also uses an eight position eight contact modular connector eight p eight c just like the RJ 45 is a matter of fact, it’s often thought of as being an RJ 45.
But it’s used as the terminating connector at the demark point for T one lines. And as I said just a moment ago, it’s often confused with the RJ 45 but the active pins are different. Then we have the UTP coupler, the unshielded twisted pair coupler. It’s used to connect UTP cables back to back and still maintain adherence to industry standards, you might still come across the 66 block being used for network connections, but probably not.
It’s a punch-down block that was initially developed to terminate in distributed telephone lines in an enterprise network.
So you might still see it for telephony, but it’s getting a little bit harder to find it. It was also used in slower speed networks as it can handle data traffic that’s rated for cat three cablings, much more likely you’ll find a 110 block. Now, this is a punch-down block that was developed to terminate and distribute twisted pair network cabling. It’s capable of handling the signalling requirements of the modern network.
I mentioned the DB nine or RS 232 connector earlier. Well, here we go. It is a nine pin D subminiature connector developed for asynchronous serial communication between nodes. It was a common type of connector between a computer and an external modem. And as I said earlier, it often makes up one end of the rollover cable, you might come across the DBX 25 also known as an EI a 232, or RS 232 serial connector.
It is a 25 pin D subminiature connector developed for asynchronous serial communication between nodes just like the DB nine only it was larger to provide a type of connection between a computer and an external analog modem. And it’s even less common than the DB nine. Now let’s move on to categories of twisted pair. And we begin with cat three. Cat three was rated for up to 10 megabits per second speed, that’s 10 base t networking and it had a maximum delay distance of 100 meters. By the way, unless I specify all twisted-pair cabling has a max distance of 100 meters, that 10 megabits per second weren’t quite fast enough.
So then we got cat five. Cat five is rated for up to 100 megabits per second speed, that’s 100 base T networking. And that still wasn’t fast enough. So they developed cat five E to cat five. He is rated for up to one gigabits per second, that’s 1000 base T.
Now we have cat six, cat six is rated for up to 10 gigabits per second, that’s 10 Gigabit Ethernet or 10 GB E. And with cat six, you can only get that 10 gigabits per second over a max distance of 55 meters. For some reason, they thought they needed to go more distance than 55 meters. So they developed cat six a, it has the same speed readings as cat six, but it has a max distance of 100 meters and you can still achieve that 10 gigabits per second networking.
Now that concludes this session on network cabling part one. I talked about twisted pair cabling. Then I talked about twisted pair network connectors, and I concluded with the categories of twisted pair cabling.