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Ethernet cable article for an IT supplies company

How to choose the right Ethernet cable

Ethernet cables, as you probably know, are used to connect computers, laptops, games consoles, smart devices, routers and more to provide fast and reliable wired internet and network connections.

They come in different colours and lengths, and also different categories.

Each category or “Cat” has its own specification with respect to data transmission speed, maximum bandwidth frequency, and shielding from electromagnetic interference.

So which category of Ethernet cable should you use?

This article has been written to give you some background information, explain the differences and help you decide.

Category 3 Ethernet cable is one of the oldest forms still in use today. Back in the early 1990s, it was the industry standard for computer networks. It’s an unshielded twisted pair (UTP) cable with a maximum data or voice transmission speed of 10 Mbps. Its maximum bandwidth is 16 MHz. You can still see it in older installations, but it fell out of favour when the faster Cat5 cable was introduced.

Category 5 Ethernet cable is also a UTP cable but is capable of higher transmission speeds (up to 100 Mbps) and greater maximum bandwidth (100 MHz). 100 Mbps is known as Fast Ethernet, and Cat5 cables are capable of transmitting telephone signals and video, as well as Ethernet data. It’s still seen with some legacy equipment and can be used for a lower bandwidth network, but it has been superseded by Category 5 enhanced (Cat5e) cable.

The physical construction of Cat5e cable is the same as for Cat5, but it’s tested to a higher standard for eliminating crosstalk (XT) – the unwanted interference between data channels. Cat5e is a very popular Ethernet cable, and is capable of 1,000 Mbps (which is known as Gigabit Ethernet). The cables can support a maximum bandwidth of 100 MHz, and can be used in most modern network installations.

The newer Category 6 cables, however, have better data transmission performance over Cat5e. They are also certified for Gigabit Ethernet speeds (1,000 Mbps) but have a bandwidth of up to 250 MHz. Cat6 cables can be UTP (unshielded twisted pair) or STP (shielded twisted pair), and have more twists per centimetre and better insulation than Cat5 cables. This helps to reduce crosstalk and makes them better suited for areas with higher electromagnetic interference.

The difference between UTP and STP cable is that – for STP – the individual pairs of twisted wires that make up the cable have a shield around them. This gives them extra protection from interference compared to the unshielded (UTP) version.

Category 6a cable (where a stands for augmented) builds on the performance of Cat6. It has a maximum data transmission speed of 10,000 Mbps (10 Gbps) and a maximum bandwidth of 500 MHz. The cable is STP.

Category 7 is a fully shielded cable that supports speeds of up to 10 Gbps and bandwidth up to 600 MHz. It’s the highest standard of Ethernet cable that’s currently available, and provides the highest protection against crosstalk and interference.


When setting up a network or internet connection in your home or office, you need to choose the right Ethernet cable. Things to consider include price, data transmission speeds, bandwidth and the likelihood of interference from other cables and devices.

Cat5e is suitable for many set-ups – but if speed and bandwidth are important then you may want to opt for Cat6 or Cat7. They would help to future-proof your network, and would also be better if you’ve lots of devices connected to it.

Bear in mind, though, that network transmission speed will depend on all the components in your network. So if you have a ‘slow’ legacy device or component in your network, the overall performance won’t be improved by using a faster cable.


David Bain

Write On Target


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