Transmission media

Transmission Media

Two types of transmission media:

1) Physical transmission media/Guided media/Wired

• Twisted-Pair Cable,Coaxial Cable,Fiber-Optic Cable

2) Wireless transmission media/Unguided media/Wireless

• Infrared,Broadcast Radio,Cellular Radio,Microwave, communications satellite

Physical Transmission Media

Device	Description of guided media(Physical Transmission Media)
Twisted Pair Cable	• Twisted-pair cable consists of one or more twisted-pair wires bundled together.
	•Widely used transmission media for network cabling and telephone systems.
Coaxial cable	Consists of a single copper wire surrounded by at least three layers:
	1.An insulating material
	2.A woven or braided metal
	3.A plastic outer coating .
Fiber optic	A transmission media that uses glass or plastic fiber to carry light (laser) signals.

Wireless Transmission Media

Device	Discription of Wireless Transmission Media
Infrared	Infrared (IR) is a wireless transmission medium that sends signals using infrared light waves.
Broadcast radio (Bluetooth, Ultra Wideband (UWB), Wi-Fi and WiMAX	A wireless transmission medium that distributes radio signals through the air over long distances such as between cities, regions and countries and short distances such as within an office or home.
Cellular Radio (2G,3G,4G)	A form of broadcast radio that is used widely for mobile communications, specifically wireless modems and cell phones
Microwave	Microwaves are radio waves that provide a high-speed signal transmission.
	* Microwave transmission, often called fixed wireless, involves sending signals from one microwave station to another.
Communications Satellite	Is a space station that receives microwave signals from an earth-based station, amplifies (strengthens) the signals, and
	broadcasts the signals back over a wide area to any number of earth-based stations.

Computer Network

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ABOUT COMPUTER NETWORK

What is network?

• A network is a collection of computers and devices connected together via communications devices and transmission media.

COMMUNICATIONS DEVICE & TRANSMISSION MEDIA

What is communication device?

• A communications device is any type of hardware capable of transmitting data, instructions, and information between a sending device and a receiving device.

What is transmission media?

• Materials or substances capable of carrying one or more signals in a communication channel.

COMMUNICATION DEVICE

Devices	Description
Dial-up Modem	A communications device that can convert digital signals to analog signals and analog signals to digital signals,so that data can travel along an analog telephone line.
Digital Modem(ISDN,DSL,Cable Modem)	A communications device that sends and receives data and information to and from a digital line
Wireless Modem	Some mobile users have a wireless modem that uses the cell phone network to connect to the Internet wirelessly from a notebook computer, a smart phone, or other mobile device.
Network card	Sometimes called a network interface card, is a communications device that enables a computer or device that does not have built-in networking capability to access a network.
Wireless access point	A central communications device that allows computers and devices to transfer data wirelessly among themselves or to transfer data wirelessly to a wired network .
	*Wireless access points have high-quality antennas for optimal signals.
Router	A communications device that connects multiple computers or other routers together and transmits data to its correct destination on a network.
Switch	A connection device similar to a hub but more sophisticated, including functionality that allows it to control and manage data transmissions.
Hub	A connection device that allows multiple connections to the network.