Network cables – why all rainbow colours and different types?

When is comes to network cables we often get asked something on the lines of “Do I use the grey or yellow cable?”. You’ve probably asked this question yourself at some point, you may have even wondered into a shop to buy a network cable and wondered which one to go for? Red, yellow, grey, black, CAT 5e or CAT 6 (we assume you understand the length you need), or you may even have spotted a Crossover cable and thought, “Is that the one I actually need?”.

Well let’s end the confusion here. Yes, that are a variety of network cables, in fact you can buy the relevant tools and components to make up your own cables to your own specific length, it’s actually quite simple.

So what’s going on? Let’s start with understanding CAT5e and CAT6

CAT 5e

The long running and wildly used CAT5e (or Category 5 enhanced) reduces crosstalk can allow data to transmit at speeds up to 1 Gigabit per second and can be a maximum length of 100 metres (just a little under in reality approx 99.9744 metres)


A newer standard and the greatest advantage is that is can allow data to transmit at speeds of up to 10 Gigabit  per second, but this comes at a price in that the maximum cable length is limited to 50 meters (or 49.9782 metres)

(For those wondering what Crosstalk is, in brief its electric or magnetic field disturbance)

So CAT 6 is quicker, and costs just a little more, although still affordable. But should you rush out and replace all of your office network cables with it? Hold your horses there. In order to hit speeds of 10 Gbps you need the appropriate hardware. Most small  / medium office network switches (where all the cables come together and allow computers to communicate with each other) will only run at 10/100/1000 speed (or 10 Mbps / 100 Mbps / 1Gbps)

in addition many computers network cards will only run at 1Gbps per second so even putting in CAT 6 cables the maximum speed you will ever get is 1Gb unless you upgrade your network hardware.

For the home user on cables it’s even worse. The chances are you don’t have a network switch. it may allow you to connect up to 4 devices to it via a network cable, but in fact what you have is a HUB, which is not a smart as a Switch and runs at a maximum speed of 100 Mbps

(TIP, If your office computers keep disconnecting have a look at your device where the cables come together and if it says “HUB” on it, go out and buy a “Switch”. see our Blog Network Switches Vs Hubs )

If you are putting in netwok cables under your floors and the distance is less that 50 metres, then go for CAT6, You maybe in that office for a while, and at some point the prices will drop even further.

Crossover Cable

Quite simply put computers on cables need to communicate with each other, and at its most basic they transmit and receive data. Inside your network cable are smaller cables each with colours and stripes on them. If a cable were plugged in directly from one computer network card to another, and the Orange cable is used for transmitting data and the blue for receiving data then what will happen if Computer A tries to transmit data to computer B? It will never get there. Well technically it will if Computer B is not transmitting, but it’s on the wrong line, Computer A is transmitting data to computer B’s transmitting port. It needs to send the data to computer B’s receiving port so in order to do this we use a Crossover cable.

But what’s with the colours?

Nothing. They are identical and do the same thing. The only difference is their colour. So why do we have them?

From a technician’s point of view it makes our life easier when trying to get through the mass of cables in your back-end server room or trying to figure out why a device has the wrong IP address or not connecting. Grey or black cables are often used to connect Computers, Purple cables to connect peripheral devices such a media, telephones etc, maybe green for printers, Red cables for DO NOT DISCONNECT ELSE THERE WILL BE TROUBLE such as a cable plugging into a server or your firewall and internet. We may even have different coloured cables for each department or floor of your building.

We simply co-ordinate the cable colours so we can see at a glance what they might be connected to. It makes our life easier.


We have been in many serviced offices and computer rooms and often come across this sort of thing (pic to the right) all the time.

You try tracing cables back in this? It’s not uncommon, but shows a lack of enthusiasm for the job, it makes life a little more awkward and increases the chances of tracing and unplugging the wrong cable.

No, what a computer room should look like is more on these lines.