Views: 22 Author: Cradian Publish Time: 2021-08-10 Origin: Site
The network ptach cord is very important in our daily life,it is the connection between computers and computers,computers and other nerwork equipment,help delivery the message.It is usually divided with 3 types:twisted-pair cable,coaxial cable and optical fiber cable.
The introduction for the twisted-pair cable
The most we called for the network patch cord or network cable is the twisted-pair cable.It is the most commonly used transmission mediun in general cabling engineering.It is made up by two copper conductors and insulating jacket(PVC or LSZH),connect with RJ45 modular plug.The length and color can be customized by random.
In this way,not only can resist part of the electromagnetic interference from the outside,but also can reduce the mutual interference from other pairs of standard wires.When 2 inslulated wires are twisted together,the interference signal acting on the 2 entangled wires is the same(this interference signal is common-mode signal).The common-model signal can be eliminated in the differentila circuit that receives the signal,thus extracting the useful signal(differential-mode signal)
To differentiate the diameter of cable,the United States developed the AWG(American Wire Gauge),it is also called Brown&Sharpe Standard.The number in front of the AWG indicateds the number of holes the wire must pass through before forming its diameter.The larger of the number,the higher of the grade of holes the wire can pass through,and the smaller the diameter of the wire.At the same time,the bigger of the number,the thinner of the wire.Thick cable has better physical strength and low resistance,but the thicker of the cable,the more copper need to make the cable,which makes it heavier,harder to install and more expensive.
AWG Reference Form
The method of connectiong wire(start from the left )
TIA/EIA-568A:white green-green-white orange-blue-white bule-orange-white brown-brown
TIA/EIA-568B:white orange-orange-white green-blue-white blue-green-white brown-brown
What is STP(STP/FTP or SFTP) or UTP?
Depending on whether there is a shield,it can be divided into Shielded Twisted Pair(STP) and Unshielded Twisted Paird(UTP).
There is a metal shield between twisted-pair cable and outer insulation envelope.
STP is the type that each cable has its own shielding layer.
FTP works only when the entire cable is shielded and both ends of the cable are properly grounded.So the whole system is required to be shieded devices,including cables,information points,modular plug and patch panel.At the same time,the building also need to have a good grounding system.The shielding layer can redyce radiation,prevent information from being eavesdropped and the entry of external electromagnetic interference.It makes the shieded twisted pair cable have a higher transmission rate than rge same kind of unshielded twiested pair cable.
UTP is a data transmission line,consisting of 4 pairs of different color transmission lines,widely used in the ethernet and telephone lines.It has the following advantages:
No sheilded Jacket,small diameter,saving space and low cost
Light weight,easy to bend and install
Minimize or eliminate crosstalk
Independent and flexible,suitable for structured cabling
SFTP,add a layer of woven net to the aluminum foil,the most used is aluminum magnesium wire woven mest,sometimes will also use the tin wire or tinned copper wire.It is more antin-interference and high security transmission,usually used in the professional wiring engineering.