These multicore wires are known as twisted pair cables.

​

Twisted pair cables were first used in telephone systems by Alexander Graham Bell in 1881. By 1900, the entire American telephone line network was either twisted pair or open wire with similar arrangements to guard against interference.

​

Today, most of twisted pair cables in the world are outdoor landlines, owned by telephone companies, used for voice service, and only handled or even seen by telephone workers. The majority of data or Internet connections also use these wires.

​

Modular Plugs

​

To connect these wires to phones and computers, the wires are crimped into plugs known as modular plugs.

​

Modular plugs have a standardised naming scheme. In the picture on the right you can see that there are 8 pins (positions) that wires can be connected to. If all 8 wires are connected, it would be an 8 position 8 connection plug - an 8P8C.

It follows that a 6P6C plug would have 6 positions and 6 connections. Equally you could have a 6P4C plug which has 6 positions but only 4 wires connected.

Quite straightforward? Well, sometimes a modular plug is specified by what plug socket it will go into and the wiring connections in that socket which is an American standard that is sometimes quoted. This system uses an RJ code to define how the plug is to be wired.

And it can get complicated, so to avoid confusing the life out of you, let’s leave that to the wiring experts – this cross reference is perfectly OK for selecting the right crimping pliers:

​

                                 6P4C = RJ11

                                 6P6C = RJ12

                                 8P8C = RJ45

​

So what exactly is the role of the modular plug crimping pliers?

​

Quite simply, it presses the wires into the connectors in the plug, making sure they are all in the right places and secure.

There is an important aspect to note when crimping modular plugs, that there is a specific order that the wires need to go into the modular plugs.