A network cable is a long cable with coloured sheath, and at both ends it has RJ45 connectors (Registered Jack 45). The RJ45 is a physical interface used for attesting (ie the insertion of the connectors at the ends of a cable) of electric cables to cross-wire pairs (twisted pair). This specific connector is part of a series of modular conductors used in the field of telecommunications and data transmission. It is a 8P8C connector, or 8-position and 8 contacts (pins), which can be used for different applications.
The pairs of a network cable
Inside the protective sheath are 4 pairs (each pair consisting of a transmission line consisting of 2 twisted copper wires), responsible for the transmission of data from one network device. The pairs are recognised from each other through identifying colors. We will then have 1 blue pair (a colored cord full and a striped cord), 1 orange pair (a colored cord full and a striped cord), 1 green pair (a colored cord full and a striped cord) and 1 ocher pair (a colored cord full and a striped cord). To prevent electromagnetic interference with other cables or other electronic equipment, the pairs can be protected using a special shielded sheath, found just beneath the plastic.
Straight and crossover cables Cables
The first big difference between network cables is in the arrangement of twisted pairs within the RJ45 connector. Depending on how the endings of the four pairs are holding the 8 positions of the connector, you will have different network cables.
If the cable routing is the same at both ends of the Ethernet cable we will have a network straight cable; if the cables of the 4 twisted pairs intersect their positions at both ends, we will talk of crossover cables.
Straight network cables are used to connect a network device – for example from the printer to the computer – to a router or a switch; the cross-network cables are used to connect directly between two PCs.
Network cable types
Under the plastic sheath of a network cable you can hide a second protective sheath, which shields pairs from electromagnetic interference. This allows to identify various types of Ethernet cables:
UTP: Unshielded Twisted Pair
FTP: Foiled Twisted Pair
STP: Shielded Twisted Pair
Network cable categories
The quality of the materials used in the construction of a network cable is another element of differentiation and it determines cables categories
Category 3 and Category 4: no longer on sale because of the lack of compatibility with the standard 100BaseT
Category 5: replaced by Category 5e Ethernet cable
Category 5e: Leverages data transmission frequencies up to 350 MHz, according to the rules of the 1000BaseT standard (data transmission of up to 1 gigabit per second)
Category 6: characterized by zero connection errors and better value / signal / noise
Category 6e: improved version of the previous, sees working frequencies up to 500 MHz and is tested to send data at a constant speed of 1 gigabit up to 100 meters away
Category 7: the best on the market today. Tested to work with frequencies of 600 MHz, it has a double shielding and supports 10BaseT standard, 100BaseT, and 1000BaseT. Ideal for business connections