CAT5 – Copper Network Solutions Choice

Defined by the Electronic Industries Association and Telecommunications Industry Association (commonly known as EIA/TIA), CAT5 (Category 5) cable is the copper wiring using twisted pair technology, designed for Ethernet networks. The term “Category” refers to the classifications of UTP (unshielded twisted pair) cables. Since its inception in the 1990s, CAT5 has become one of the most popular types of of all twisted pair cable types which include CAT3, CAT4, CAT5, CAT6, etc. This article details CAT5 used in copper networks from its working principles, its standard, as well as its installation considerations.

How CAT5 Cable Technology Works

CAT5 is widely used in 100BASE-TX and 1000BASE-T Ethernet networks. CAT5 typically contains four pairs of copper wire. In 100BASE-TX standard, the signals are transmitted across only two of the CAT5 pairs. One pair is used to transmit signals, and the second pair receives the signals, leaving the other two unused in signal transmission. What’s more, the 100BASE-TX signals only run in one direction across the pairs. As technology advanced, the 1000BASE-T Gigabit Ethernet (GbE) standard was developed. 1000BASE-T standard utilizes all four copper pairs to transmit up to 250 megabits of data per second (Mbps) in full duplex transmission across each pair. That is to say, each pair is able to transmit and receive signals simultaneously. 1000BASE-T modules (eg. GLC-T) functioning over CAT 5 with RJ-45 connector achieve full duplex transmission with link length up to 100m (328ft).

GLC-T, functions over CAT 5 with RJ-45 connector

There are two standards for CAT5 wiring, EIA/TIA-568A and EIA/TIA-568B. The following passages mainly discuss EIA/TIA-568A.


The TIA-EIA-568-A standard defined the following three main parameters for testing Category 5 cabling installations: wiremap, attenuation, and Near End Crosstalk (NEXT).

Wiremap is a continuity test. It assures that the conductors that make up the four twisted pairs in the cable are continuous from the termination point of one end of the link to the other. This test assures that the conductors are terminated correctly at each end and that none of the conductor pairs are crossed or short-circuited.

Attenuation is the loss of signal, as it is transmitted from the end of the cable to the opposite end at which it is received. Attenuation, also referred to as Insertion Loss, is measured in decibels (dB). For attenuation, the lower the dB value is, the better the performance is, and of course less signal is lost. This attenuation is typically caused by absorption, reflection, diffusion, scattering, deflection.

Near End Crosstalk (NEXT) measures the amount of signal coupled from one pair to another within the cable caused by radiation emission at the transmitting end.If the crosstalk is great enough, it will interfere with signals received across the circuit. Crosstalk is measured in dB. The higher the dB value, the better the performance, more of the signal is transmitted and less is lost due to coupling.

NEXT: the amount of signal coupled from one pair to another

CAT5 Installation Considerations

After testing parameters are mentioned above, here goes the notes of CAT 5 installation.

  • Never pull CAT5 copper wire with excessive force. The CAT5 tension limitation is 25 lbs, much lower than standard audio/video cable.
  • Never step on, crush, or crimp CAT5.
  • Avoid periodic sags; vary the intervals if the cable must sag.
  • Do not bend CAT5 wire tightly around a corner; ensure that it bends gradually, so that a whole circle would be at least two inches in diameter.
  • Do not allow knots or kinks, even temporarily.
  • Never run CAT5 parallel to power wiring closer than six inches.
  • Avoid splices. Every splice degrades the line.

Although CAT5 is superseded by CAT5e in many applications, most CAT5 cable meets Cat5e standards and it’s still a commonplace in Local Area Networks (LANs). Many copper networks choose CAT5 as their transmission media because of its low price and high performance. Fiberstore supplies many CAT5 RJ45 pluggable modules, like 100BASE-TX, and 1000BASE-T transceivers (eg. SFP-GE-T). For more information about copper network solutions, you can visit Fiberstore.

Guide to Coaxial Cable, Twisted Pair Cable and Fiber Optic Cable

The advancements of cable-based technologies have made wider accessibility to greater bandwidth possible in Local Area Network (LAN). With so many network options, to select a right cable-based solution for broadband connection services is a little confusing. When such factors as cost, speed, bandwidth and immunity are considered, which one is an ideal choice for networks, coaxial cable or twisted pair cable? Or is the fiber optic cable that meets your needs?

Coaxial Cable

Coaxial cable, or  in a foam insulation, symmetrically surrounded by a woven braided metal shield, then covered in a plastic jacket. Because of its insulating property, coaxial cable can carry analogy signals with a wide range of frequencies. Thus it is widely used in feedlines connecting radio transmitters and receivers with their antennas, computer network connections, digital audio, and distributing cable television signals. The following figure shows the structure of coaxial cable.

Coaxial cable, a single wire usually copper wrapped

Actually, there exists another cable, twin-ax cable, which is similar to coaxial cable, but with two inner conductors instead of one. This kind of cable comes in either an active or passive twin-ax (twin-axial) cable assembly, used for 10, 40 or 100 Gigabit Ethernet (GbE) links.Like QSFP-H40G-CU1M, this Cisco 40G cabling product is the QSFP to QSFP passive copper cable assembly designed for high-performance 40GbE networks.

QSFP-H40G-CU1M, QSFP to QSFP passive copper cable assembly

Twisted Pair Cable

Twisted pair cable is a type of wiring in which two conductors of a single circuit are twisted together. It comes in two versions: Shielded Twisted Pair (STP) and Unshielded Twisted Pair (UTP). STP is commonly used in Token Ring networks and UTP is in Ethernet networks. The image below displays what UTP (left) and STP (right) look like.

Twisted pair cable, UTP and STP

Fiber Optic Cable

A fiber optic cable is a cable containing one or more optical fibers. Fiber optic cables often contain several silica cores, and each fiber can accommodate many wavelengths (or channels), allowing fiber to accommodate ever-increasing data capacity requirements. When terminated with LC/SC/ST/FC/MTRJ/MU/SMA connectors on both ends, such as LC-LC, LC-SC, LC-ST, SC-ST, SC-SC, ST-ST etc, fiber optic cables can achieve fiber link connection between equipment.

Comparison of Three Kinds of Cables

Coaxial cable can be installed easily, relatively resistant to interference. However, it is bulky and just ideal for short length because of its high attenuation. It would be expensive over long-distance data transmission. By contrast, twisted pair cable is the most flexible and cheapest among three kinds of cables, easy to install and operate. But it also encounters attenuation problem and offers relatively low bandwidth. In addition, it is susceptible to interference and noises. As one of the most popular mediums for both new cabling installations and upgrades, including backbone, horizontal, and even desktop applications, fiber optic cable is small in size and light in weight. Because the conductor is glass which means that no electricity can flow through, fiber cable is immune to electromagnetic interference. The biggest advantage of fiber optic cable is that it can transmit a big amount of data with low loss at high speed over long distance. Nevertheless, it needs complicated installing skills, difficult to work with and expensive in the short run.

When selecting which kind of cable is appropriate for network services, one should keep in mind that each cable has its unique advantages and disadvantages concerning about these factors: cost, speed, security, reliability, bandwidth, data carrying-capacity, and so on.


Choosing among coaxial cable, twin-ax cable, twisted pair cable and fiber optic cable depends on your needs. You can balance the cost and the requirements of bandwidth to make a choice. In Fiberstore, you can find twisted pair cables and a series of fiber optic cables. Other cables, such as active optical cable (AOC) (eg. QSFP-4X10G-AOC10M) are also available for your networks. You can visit Fiberstore for more information about cable-based solutions.