WIRELESS TRANSMISSION MEDIA SUCH AS INFRARED, RADIO WAVE AND SATELLITE.

WIRELESS TRANSMISSION MEDIA SUCH AS INFRARED, RADIO WAVE AND SATELLITE..

Wireless Technology

In a wireless media however, signal transmission is unguided and the device communicates without using wires between nodes, usually by relying on radio frequencies instead.

INFRARED

• Infrared is a wireless transmission medium that sends signals using infrared light waves. Infrared is used in devices such as the mouse, wireless keyboard and printers. Some manufacturers provide a special port called the IrDA port that allows a wireless keyboard to communicate with a PC. Infrared signals have frequencies between 300 GHz to 400 THz.

RADIO WAVE

• Radio waves are a type of electromagnetic radiation with wavelengths in the electromagnetic spectrum longer than infrared light. When an antenna transmits radio waves, they are propagated in all directions. This means that the sending and receiving antennas do not have to be aligned. Our AM and FM radio stations, cordless phones and televisions are examples of multicasting.

SATELLITE

• Satellite is an object which has been placed into orbit by human endeavor. A communication satellite is a space station that receives microwave signals from an earth-based station, amplifies (strengthen) the signals, and broadcasts the signals back over a wide area to any number of earth-based stations.

MEDIUM

Identify various types of cables such as Unshielded Twisted Pair (UTP), Shielded Twisted Pair (STP), coaxial and fiber optic cable

Shielded Twisted-Pair Cable

• Its Four pairs of colour-coded wires are each wrapped in metallic foil, and all four are then collectively wrapped in a layer of metallic braid or foil. Finally, this layer is wrapped with outer jacket.

Unshielded Twisted-Pair Cable

• Consist of two wires or conductor twisted together, each with it own plastic insulation. Cancel out the electromagnetic interference that can cause crosstalk, the noise generated by adjacent pairs.

Coaxial Cable

• The coaxial cable, often referred to as ‘coax’, consists of a single copper wire surrounded by at least three layers. They are an insulating material, a woven or braided metal and a plastic outer coating. This cable is often used as cable television (CATV) network wiring because it can be cabled over longer distances in comparison to the twisted-pair cable.

Fibre Optic Cable

• The fibre optic cable is a networking medium that uses light for data transmission. The intensity of light is increased and decreased to represent binary one and zero. The binary system is a way of counting using just the two numbers 0 and 1.

DEVICES NEEDED IN COMPUTER NETWORK COMMUNICATION..

MODEM

• A modem is a device or program that enables a computer to transmit data over, for example, telephone or cable lines.
• Use to convert digital signal to analog signal and vise versa.

NIC ( NETWORK INTERFACE CARD)

• Network Interface Card (NIC) is also commonly referred to as a network adapter and is an expansion card that enables a computer to connect to a network using a given protocol.

WNIC ( WIRELESS NETWORK INTERFACE CARD)

• Wireless Network Interface Card (WNIC) is a network card that provides wireless data transmission. This card uses an antenna to communicate through microwaves.

WIRELESS ACCESS POINT

• A Wireless Access Point is a central communications device that allows computers and devices to transfer data wirelessly to a wired network using Wi-Fi, Bluetooth or related standards.

ROUTER

• A network device that forwards packets or data from one network to another according to the packet’s destination address.

SWITCH / HUB

• A hub or switch is a device that provides a central point for cables in a network. Switches allow user to send information, such as email, and access shared resources, including printers

INTERNET, INTRANET, EXTRANET

INTERNET..

- The Internet is a global system of interconnected computer networks use the standard
Internet Protocol Suite (TCP/IP) to serve billions of users worldwide

- It is a network of networks that consists of millions of private, public, academic,
business, and government networks, of local to global scope, that are linked by a
broad array of electronic and optical networking technologies

INTRANET..

- An intranet is a private computer network
- Use Internet Protocol technologies to securely share any part of an organization's
information within that organization
- Example of intranet application: telephone directories, job posting, event
calendars
- Example employees can access the company information by using username and password

EXTRANET

- An extranet is a private computer network which allows partner/vendors/customer
or suppliers to access part of its intranet.
- Also need username and password to access the company information
- Example such as an online banking application managed by one company on behalf of
affiliated banks