COMMUNICATION DEVICE

A communication devices is piece of equipment or hardware designed to move information or data from one place to another which is allowing one computer device communicate with another.


TYPES OF COMMUNICATION DEVICES.

Hub is a device that used for connecting wired computers or devices on a Local Area Network (LAN). A hub provides a common connection point for nodes on a star network.

 Modem is a device that enable to transmit computer data over telephone or cable line. Modem converts digital signals from computer into analog signals to send over the phone lines and converts the phones analog signals into digital for the computer.

Router is a device that computers and transmits data to its correct destination on the network. A router allows multiple computers to share a single high-speed internet connection.

TYPE OF TRANSMISSION MEDIA

TYPE OF WIRED

1. Twisted Pair Cable

A transmission medium consisting of pairs of twisted copper wires arranged in a regular spiral pattern to minimize the electromagnetic interference between adjacent pairs. Low frequency transmission medium only can transmit 1 Mbps over short distances. They are mainly used to transmit analog signals but they can be used for digital signals.

2. Coaxial Cable

Coaxial cable consists of a core made of solid copper surrounded by insulation a braided metal shielding and an outer cover. A transmission medium consisting of thickly insulated copper wire which can transmit a large volume of data than twisted wire.

3. Fiber-optic Cable

New transmission medium used by telephone companies in place of long-distance trunk lines. This cable also used by private companies in implementing local data communication networks. Optical fiber consists of a glass cladding with slightly lower refractive index. Fiber optic cable is used as the high speed backbone.



TYPE OF WIRELESS

·                     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 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 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.