4-Network Transmission media

First, the signal

1> information: A person's understanding of the state of the existence or movement of things in the real world

2> data: A specific measure used to describe certain properties of a thing

3> signal: The medium of information transmission

Second, the classification of the signal

1, Analog signal: continuous change of the physical quantity

2, data signal: Discontinuous physical quantity, signal parameters are not continuous change, high and low fixed

The advantages of digital signal: strong anti-jamming ability, long transmission distance, and can guarantee the quality

Three, twisted-pair wire

1. Twisted-pair line classification

1> shielded twisted pair (STP)

A layer of metal foil wrapped outside the wire for use in an industrial environment with very complex electromagnetic environments

2> unshielded twisted pair (UTP)

2. Twisted pair Standard and classification

CAT 55 line for 100MBPS Network

CAT 5E Super Five class: reduced attenuation, less crosstalk, better performance than Class 5

CAT 6 High Transmission frequency 200MHZ

CAT 7 500HMZ

Iv. Optical Fiber

Single-film fiber: For high speed, long-distance, high cost, end-connection difficult, narrow core line, need laser source, dissipation small, high efficiency

Multi-membrane optical fiber: Used for low speed, short distance, low cost, easy termination, wide core line, good spot, light source can use laser or diode, dissipation large, offset effect

Five, Ethernet interface

RJ-45 Crystal Head

Fiber Interface: FC ST SC LC Narrow-Body Square fiber interface MT-RJ

Six, information sockets

Information module: Information Socket panel

Seven, twisted pair connection specification

1. Line sequence:

T568A: White green, green, white orange, blue, white blue, orange, white brown, brown

T568B: White orange, orange, white green, blue, white blue, green, white brown, brown

Send 3,6 Accept

2, the connection of the cable

Standard cable (direct or straight line): For connecting different devices (A-a b-b)

Cross line: For connecting the same device (A-B)

Full anti-line: Not used for Ethernet connection, mainly for the computer's serial port and the router or switch console (control port) connected, its line sequence is one end of 1-8, the other end is 8-1

Special case: The computer directly connected to the router with a crossover line

The switch is connected to the switch, the straight line or crossover line can be used, the intersection line is common

Eight, the marking of the cable

Cable labels

Pipe labels

4-Network Transmission media