The 100Base-TX (sometimes referred to 100Base-T) cable was until 2010 perhaps the most popular cable around since it has actually replaced the older 10Base-T and 10Base-2 (Coaxial). The 100Base-TX cable provides fast speeds up to 100Mbits and is more reliable since it uses CAT5e cable (see the CAT 1/2/3/4/5 page).There is also 100Base-T4 and 100Base-FX available, which we discuss at the end of this article.

So what does 100Base-TX/T4/FX mean?

We are going to break the "100Base-T" into three parts so we can make it easier to understand:

100

The number 100 represents the frequency in MHz (Mega HertZ) for which this cable is made. In this case it is 100 MHz. The greater the MHz, the greater speeds the cable can handle. If you try to use this type of cable for greater frequencies (and, therefore, speeds) it will either not work or become extremely unreliable. The 100 MHz speed translates to 100Mbit per second, which in theory means 12 Mbps. In practice though, you wouldn't get more than 4 Mbps.

The cross-over (or crossover) CAT5 UTP cable has to be one of the most used cables after the classic straight-thru cable. The cross-over cable allows us to connect two computers without needing a hub or switch. If you recall, the hub does the cross-over for you internally, so you only need to use a straight thru cable from the PC to the hub. Since now we don't have a hub, we need to manually do the cross-over.

 

Why do we need an cross-over cable?

When sending or receiving data between two devices (I.E. computers) one will be sending while the other receives. All this is done via the network cable and if you look at a network cable you will notice that it contains multiple cables. Some of these cables are used to send data, while others are used to receive data and this is exactly what we take into account when creating a crossover cable. We basically connect the TX (transmit) of one end to the RX (receive) of the other!

The diagram below shows this in the simplest way possible:

CAT5 Cross-over

There is only one way to make a CAT5e crossover cable and it's pretty simple. Those who read the "Wiring UTP" article know a crossover cable is a 568A on one end and a 568B on the other. If you haven't read the wiring section, don't worry because we’ll provide enough information to help understand about the concept.

As mentioned previously, the purpose of a crossover cable to connect the transmitting side (TX) from one end, to the Receiving side (RX) at the other end, and vice versa.

Let's now have a look at the pinouts of a typical crossover CAT5e cable:

Full motion video for video conferencing requires, typically, at least 25 Mb/sec. That means that a legacy Ethernet, at 10 Mbps/sec, can only deliver poor quality real-time video. With 100 Mbps/sec, however, you can be watching a broadcast presentation in one window while you're in conference with three people in three other windows (for a total of 100 megabits of bandwidth).

Consider a file server that requires 0.6 Mb/sec (6 million bits per second; 60% utilization on a 10 Mb/sec Ethernet). With a 100 Mb/sec Ethernet this server can now utilize interface hardware that can pump data down the pipe at a greatly increased rate.

It seems clear that the evolution of the industry is moving away from 10 Mb/sec Ethernet and towards the 100 Mb/sec (or higher) rates of data transfer. This section of the compendium discusses 100 Mb/sec Ethernet technology

Virtually everyone who uses Ethernet has wished from time to time that their network had a higher bandwidth. When Ethernet was being designed in the late 1970s, 10Mbps seemed immense. With today's bandwidth-intensive multimedia applications, or even with just the departmental server, that number sometimes is barely adequate. Yes, faster network technologies were available, but they were complicated and expensive. Then came Fast Ethernet.

Anyone who understands classic Ethernet already understands much about Fast Ethernet. Fast Ethernet uses the same cabling and access method as 10Base-T. With certain exceptions, Fast Ethernet is simply regular Ethernet - just ten times faster! Whenever possible, the same numbers used in the design of 10Base-T were used in Fast Ethernet, just multiplied or divided by ten. Fast Ethernet is defined for three different physical implementations.

The Implementations of Fast Ethernet:

• 100BASE-TX: Category 5
• 100BASE-FX: Multimode fibre
• 100BASE-T4: Category 3

Probably the most popular form of Fast Ethernet is 100BASE-TX. 100BASE-TX runs on EIA/TIA 568 Category 5 unshielded twisted pair, sometimes called UTP-5. It uses the same pair and pin configurations as 10Base-T, and is topologically similar in running from a number of stations to a central hub.

As an upgrade to 10Mbps Ethernet over multimode fibre (10Base-F), 100BASE-FX is Fast Ethernet over fibre. Single duplex runs are supported up to 400m and full duplex runs are supported for up to 2km.

Fast Ethernet is possible on Category 3 UTP with 100BASE-T4. There is a popular misconception that Fast Ethernet will only run on Category 5 cable. That is true only for 100BASE-TX. If you have Category 3 cable with all four pairs (8 wires) connected between station and hub, you can still use it for Fast Ethernet by running 100BASE-T4. 100BASE-T4 sends 100Mbps over the relatively slow UTP-3 wire by fanning out the signal to three pairs of wire.

This "demultiplexing" slows down each byte enough that the signal won't overrun the cable. Category 3 cable has four pairs of wire, eight wires total, running from point to point. 10Base-T only uses four wires, two pairs. Some cables only have these two pairs connected in the RJ-45 plug. If the category 3 cabling at your site has all four pairs between hub and workstation, you can use Fast Ethernet by running 100BASE-T4.

Please select on of the following sections:

Network cabling is one of the most important aspects in any network infrastructure and has become increasingly critical with the introduction of newer technologies such as blade servers, virtualization, network storage devices, wireless access points and more.

Network services such as file sharing, Internet access, network printing, email, ERP systems and more, are all delivered to the end users via the network infrastructure, which usually includes switches, fiber optic links and of course UTP cabling.

This series will focus on the different type of Ethernet copper cabling specifications, speeds and caveats of each technology.

We’ll continue with the expansion of our covered topics to cover fiber optic technology and talk about the different fiber optic cables available in the market and then jump back into the past by covering various direct cable connections used to transfer data between computers. This last section will cover extensively serial, parallel, usb ports and their different specifications/versions, plus we’ll get to talk about the variety of cables used to connect between these old-technology ports.

While many might believe the last section of this series might contain information not considered useful (serial, parallel & usb ports), you’ll be amazing on how much of this information will actually come in handy at some point in the future.

All material covered includes detailed diagrams and has been checked to ensure it is as accurate as possible.

This article covers the commonly known Unshielded Twisted Pair (UTP) cable and shows how many pairs the UTP Cat5, Cat5e, Cat6 & Cat7 cables consists of, the colour coding they follow, the different wiring standard that exist (T-568A & T-568B) plus the pin number designations for both standards.

We will be mainly focussing on the wiring of CAT5e & 6 cables as they are the most popluar cables around! We'll also cover wiring classic CAT1 phone cables. It is very important to understand UTP cabling standards and how to correctly terminate them.

Cabling is the foundation for a solid network, and implementing it correctly the first time will help avoid hours of frustration and troubleshooting. On the other hand, if you are dealing with a poorly cabled network, this knowledge will help you to find the problem and fix it more efficiently.

Wiring the UTP cables

We are now going to look at how UTP cables are wired. There are two popular wiring schemes that most people use today: the T-568A and T-568B. These differ only in which color-coded pairs are connected -- pairs 2 and 3 are reversed. Both work equally well, as long as you don't mix them. If you always use only one version, you're okay, but if you mix A and B in a cable run, you will get crossed pairs.

UTP cables are terminated with standard connectors, jacks and punchdowns. The jack/plug is often referred to as a "RJ-45," but that is really a telephone company designation for the "modular eight-pin connector" terminated with the USOC pinout used for telephones. The male connector on the end of a patch cord is called a "plug" and the receptacle on the wall outlet is a "jack."

Figure 1. A RG-45 Jack and RJ-45 Plug / Connector

 

As already mentioned, UTP has four twisted pairs of wires. The illustration shows the pairs and the color codes they have. As you can see, the four pairs are labeled:

Figure 2. Colour codes & Pairs of UTP CAT 5, CAT 5e, CAT6, CAT7 Cable

Pairs 2 and 3 are used for normal 10/100 Mbps networks, while pairs 1 and 4 are reserved. In Gigabit Ethernet, all four pairs are used.

The picture below shows the end of a CAT5e cable with an RJ-45 connector, commonly used to connect computers to a switch. It also shows a stripped CAT5e cable and identifies the four twisted pairs: