Communication Devices/What Is Hub

Communication Devices.

The Hardware used to transmit data instruction and information between a sending and receiving device is called communication device. A communication device at sending and send data to a communication channel a communication device at receiving and receive data from communication channel. Sometime the communication device may also convert the data from digital to analogue and analogue to digital signals.

Some important communication devices are as follows:

Dialup Modem

Modem is a communication device that send and receive data from one computer to another on the Internet through telephone line. Britannic and Seema computed both must have died of modern computer store information in the form of digital signal. However, the information transmitted over the telephone line is in the form of analogue signals that dial-up modem receive data from computer in digital form and convert it into analogue form this process is called to  Modulation. It had the analogue signal to other computer using telephone line with the dialogue modem and save in computer receive data in analogue form it convert the analogue data back into digital form this process is called Demodulation.

Dial up connection must be established which time the modem is used it provide a transfer rate up to 56kbps  and it must slower than broadband connection dial-up modem is not used today.

Digital Modem

Digital modem is called broadband modem different type of digital modem are as follows:

1. ISDN Modems

An ISDN  modam send the digital data and information from a computer to an ISDN line and receive digital data and information from an ISDN and line. It provide the data transfer rate upto 1.54 mbps.

2. DSL Modem

DSL  madam aap broadband modem that send with digital data and information for  a computer to a DSL line and receive digital data from a DSL line DSL modem is typically and external device that connects to the phone line at one end and a port on the computer at the other and it allows fast transmission over the standard telephone line then ISDN and bottoms.It provide the data transfer speed up 384 KB per second to 20 MB per second.

3. Cable Modem

Cable modem is a broadband modem that sends and receives data over the cable television network it provides fast Internet speed than dial-up modem DSL modem and ISD and it provide a speed of 8 MB per second to 50 MB per second.

Wireless Modem

Wireless modem to transmit the data signal through the air instead of cable it is also known as radio frequency modem. It is designed to work with cellular technology and wireless Local area network. Most handheld computers Smartphones and other mobile devices used the wireless modem to connect the internet wirelessly. It can also be used with notebook and desktop computers.

Network Interface Card

Network card is a communication device used to connect a computer to a network it is also called network interface card. It is a circuit board  installed on the motherboard no a day most computer system have a computer card built into the motherboard is computer on the network must have a network card. There are different network card available at work card for test of computer is an adaptor card. It has a port to connect the cable network card for mobile. Computer is in the form of USB adaptor, Express Card module etc.

A wireless network card is used to transmit data wirelessly. It usually had an antenna that can be positioned  properly for the best signal booked an amplifier can be used for increasing the signal strength some network cards the support wide as well as wireless networks.

Wireless Access Point

Wireless access point is a communication device that allows the computer and other devices to transfer data wirelessly among themselves or to avoided network. It acts as a central transmitter and receiver of wireless radio signals. It has antenna to provide better signals. The wireless access points support Wi-Fi and are most commonly used to support public internet for sport at airports hotels are coffee shop etc. They are also used in business networks where larger building and space in need wireless coverage.

Hub

A hub  also called  concentrator are multi-station accept unit. It provides a central point for cables. In a network of house also transmit Signals and have multiple port to which device are connected. IT hub connects the computer to a network it broadcast or messages to every computer on the network but only the intended recipient computer text the message. The computer that are not the recipient of the messages ignored the messages.  A hub can handle only one way information traffic at a time.

Switch

Network switch is more intelligent device than hub.  Which improve the efficiency of the data transfer in the network. It receives a message from any device connected to the network and then transmit the message only to that device for which the message was meant. It can also handle multiple communication with channels at the same time.

Routers

Router is a communication device connect multiple network using similar or different protocol called IT manager at the best route between any two communication networks .Router are used when several networks are connected together. A router can be used on the network of any size if it can be connected networks of different countries and their transfer data in less time. The router is an intelligent device it use algorithm to find out the best path to transfer data to the network.

Gateway

Gateway is a device that connects two or more networks with different type of protocol, that it is an intelligent device that it can convert data according to the protocol. A Gateway can be used to connect a personal computer network to Mainframe computer network.

Bridge

A network Bridge can be used in computer networks to interconnected to land and two separate network segments assignment in and section of a network. When a bridge receive a signal  it determined the segment where the signal should be sent. It read the attractive of sending and receiving computer. The bridge does not pass the signal to the others sending and receiving computer are both in the same segment It reduces network traffic and increases network performance.


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