Basics of networking

1. Construction:

·         8 copper wires braided into 4 pairs,

·         Outer shirt.

It is terminated with an RJ45 connector, also known as 8P8C.

Depending on the type of twisted pair cable, there are also protective foils and screens to protect the cable from unwanted elements that can affect data transmission, such as electromagnetic waves.

2. Types of twisted pair cable:

·         UTP - unshielded twisted pair,

·         FTP - foil shielded twisted pair,

·         STP - twisted pair shielded cable.

In practice, we may encounter different variants of the above types, the most important of which are:

·         U/UTP - unshielded twisted pair

·         F/UTP - foiled twisted pair

·         U/FTP - twisted pair cable with each pair in a separate foil screen,

·         F/FTP - twisted pair with each pair in a separate foil screen and additionally the whole bundle also in a foil screen

·         S/FTP - twisted pair with each pair in a separate foil screen and additionally the whole bundle in a mesh screen.

The most common material used in twisted-pair shielding is polyester film coated with a layer of aluminium and copper.

The type of twisted-pair cable that should be chosen to build a network depends on where the network is operating and the level of electromagnetic interference present in the location. In small local area networks, whether in a school or at home, the basic UTP type is most commonly used because it is sufficient for such a small network and is also the cheapest type of twisted pair cable.

3. Twisted pair cable categories

In addition to twisted pair types, there are classes that define, among other things, the network standards in which they can be used.

 4. Technical parameters

·         Signal attenuation - is the ratio of output voltage to input voltage, expressed in decibels [dB]

·         Signal propagation - is the speed of the electrical impulse relative to the speed of light, expressed as a percentage [%].

·         Resistance - is the resistance of a cable to current expressed in ohms [Ω].

·         Near Crosstalk (NEXT) - is interference in a given set caused by data transmission in a neighbouring set

Also from an installation point of view, an important parameter is the bending radius of the cable, which, for most solutions, is 4 times its outer diameter.