Media is the most powerful entity on the earth.
1) Media is of two types guided and unguided
2) Guided is physical connection and is of three types
Coaxial
Twisted pair
Fiber optic
3) Twisted pair is again classifed into two types they are unsheilded twisted pair(UTP) and sheilded twisted pair(STP)
4) Unguided is wireless connection and of two types
infrared connection
radio frequency connection
Coaxial cable, or coax, is a type of cable that has an inner conductor surrounded by a tubular insulating layer, surrounded by a tubular conducting shield. Many coaxial cables also have an insulating outer sheath or jacket. The term coaxial comes from the inner conductor and the outer shield sharing a geometric axis.
Twisted pair cabling is a type of wiring in which two conductors of a single circuit are twisted together for the purposes of canceling out electromagnetic interference (EMI) from external sources; for instance, electromagnetic radiation from unshielded twisted pair (UTP) cables, and crosstalk between neighboring pairs..
An optical fiber cable is a cable containing one or more optical fibers that are used to carry light. The optical fiber elements are typically individually coated with plastic layers and contained in a protective tube suitable for the environment where the cable will be deployed. example long distance telecommunication, or providing a high-speed data connection between different parts of a building.
IR, or infrared, communication is a common, inexpensive, and easy to use wireless communication technology. IR light is very similar to visible light, except that it has a slightlty longer wavelength. This means IR is undetectable to the human eye - perfect for wireless communication. For example, when you hit a button on your TV remote, an IR LED repeatedly turns on and off, 38,000 time a second, to transmit information (like volume or channel control) to an IR photo sensor on your TV.
Radio frequency (RF) is any of the electromagnetic wave frequencies that lie in the range extending from around 3 kHz to 300 GHz, which include those frequencies used for communications or radar signals.RF usually refers to electrical rather than mechanical oscillations. However, mechanical RF systems do exist (see mechanical filter and RF MEMS).
TYPES OF CABLE CONNECTIONS
STRAIGHT CABLE
You usually use straight cable to connect different type of devices. This type of cable will be used most of the time and can be used to:
1) Connect a computer to a switch/hub's normal port.
2) Connect a computer to a cable/DSL modem's LAN port.
3) Connect a router's WAN port to a cable/DSL modem's LAN port.
4) Connect a router's LAN port to a switch/hub's uplink port. (normally used for expanding network)
5) Connect 2 switches/hubs with one of the switch/hub using an uplink port and the other one using normal port.
cross cable
Sometimes you will use crossover cable, it's usually used to connect same type of devices. A crossover cable can be used to:
1) Connect 2 computers directly.
2) Connect a router's LAN port to a switch/hub's normal port. (normally used for expanding network)
3) Connect 2 switches/hubs by using normal port in both switches/hubs.