For the construction of computer networks using a special Ethernet cable (Lan-кабель).There are several main types of such wires: twisted pair, coaxial and fiber optic. The first type is considered the cheapest and simplest, so more than 90 percent of all local networks use it.
This Ethernet cable is the most common and famous.It consists of eight copper conductors, which are intertwined in pairs. PVC plastic is used as an insulating material. There are many types of twisted pair, differing from each other type of protection or lack thereof. Protective function can be performed by aluminum foil wrapped around the wires, or copper braid of each pair. In addition, there are combined types of protection. Shielded ethernet cable more resistant to external interference, butaccordingly, has a greater value. There are also several types of twisted pair, which are labeled “CA”, which defines the category of wire. There are seven types of this parameter. The higher the category number, the greater the cable capacity, that is, the more conductors are used. So, the seventh category of twisted pair (the last one for today) allows you to transmit information at a speed of 40 Gbit / s. To ensure this speed without distorting the signal, each pair of conductors in the cable must have a characteristic impedance of 100 ohms.
Этот вид провода состоит из экрана и проводника, having a common axis of rotation. The cable contains a conductor, insulator, PVC-sheath, copper or aluminum braid. Today, this type of wire is used as a conductor for antennas. There are practically no local networks organized on coaxial cables. The most common wire with a characteristic impedance of 50 Ohms - for computer networks - and 77 Ohms - for the transmission of a television signal. The maximum data transmission capacity is 10 Mbps. In addition, it is impractical, as it is rather difficult to repair damaged areas, which subsequently leads to significant losses.
These Ethernet cables are characterized by lowattenuation level, even when transmitting data over long distances, they are not subject to interference. In addition, the optical fiber has a high broadcast speed. For repair of the cable in question, specialized tools and equipment are required, and for connection, spectral equipment will be needed. This type is rarely used for laying networks in an apartment or office, because, in addition to sophisticated equipment, it has a rather high price.
Standard four-pair cable twisted pair forbuilding local networks crimped connector type RJ-45. The wiring diagram has the following order: white-green, green, white-orange, blue, white-blue, orange, white-brown and brown wires. Crimping schemes differ depending on the purpose of the connecting lines, technology and information transfer standards. Sometimes use direct and reverse (cross) crimp connector.
