Communication Devices

Communication Devices

 The hardware used to transmit data, instructions and information between a sending and  receiving device is called communication device. A communication device at sending end sends data to a communication channel. A communication device at receiving end receives data from communication channel. Some communication devices are as follows: 

Modem

Modem stands for modulation and demodulation. Modem is a device that converts digital signal into analog  and analog signal into digital. Modem sends and receives data from one computer to another  through telephone lines. The sending and receiving computers both must have modems. A process of converting digital signal is called modulation. Computer stores data using telephone line, so it is converted from digital to analog form. A process of converting analog signal into digital signal is called demodulation. The modem on receiving computer receives data in analog form and converts it into digital format to be used by the computer.

Network Interface Card

Network Interface Card (NIC) is also called LAN adapter. It is used to connect a devices to a network. The transfer rate of an Ethernet card is from 10 Mbps to 1000 Mbps to 1000 Mbps. Different NIC are available for different types of computers. Network cards for wireless data transmission are also available. These adapter cards often have an antena.

Wireless Access Point

 A wireless access point is a central communication device. It allows computer and other devices to transfer data wirelessly among themselves or to a wired network.Wirless access points have high quality antennas for optimal signals. Some manufactures suggest to place the wirless access point at the highest possible location for the best signal.




Routers
A router is a communication device that connects multiple computer or other routers together. It connects multiple networks using similar or different protocols. It manages the best route between any two communication networks. Routers are used when several networks are connected together. They can connect networks of different countries. They transfer data in less time. The router is an intelligent device. It uses algorithms to find out the best path to transfer data to network.

HUB

A hub also called concentrator or multistation access unit (MAU). It provides a central point for cables in a network. Hubs also transmit signals and have multiple ports to which devices are connected. It broadcasts all messages to every computer on the network but only the intended recipient  computer takes the message.The computer that are not the recipients of the message ignores the message.A hub can handle only one-way  information traffic at a time.