Flashcards
Data communication
Cards in this deck (38)
- 1What is data communication?Data communication is the transmission of data and information between 2 or more computers
- 2What is data communication essential for?It is essential for electronic, voicemail,telecommuting, facsimile, telemarketing, bulletin board and video conferencing.
- 3How is data moved?Data is moved from one location to the other via communication channels or links.
- 4How are the channels classified?According to bandwidth..
- 5What does the bandwidth determines?It determines the volume of data that can be transferred at a given time.
- 6The wider the bandwidth?The more data it can transmit.
- 7How many groups are bandwidth classified in?3 groups:
Narrow-band Channel
Voice band channel
Broadband Channel - 8Narrow band channelThis channel is almost absolute such as the telegraph. It transmits data at very slow speeds at 10 to 30 characters per second.
- 9Voice band channelIt transmits data up to 1000 to 8000 characters per second and is widely used in telephone lines.
- 10Broadband ChannelThis channel has a speed of over 10000 characters per second. The coaxial cable, fibre optic cable, microwave links and communication satellites provide these channels.
- 11What are the two configurations?Point to Point
Broadcast - 12Point to PointThis is a direct link between two computers in a network.
- 13BroadcastThis is used in one computer that transmit data and information to serve the needs of several terminals or computers connected to it in a network.
- 14What is a communication channel?This is a method or medium used for transmitting data.
- 15What are the characteristics of Communication channels?Transmission mode, direction of data flow, types of transmission mediums and transmission speed.
- 16What is a communication mode or transmission mode?This determines the amount of characters that can be transmitted per second.
- 17Examples of Communication modes are?Simplex
Half duplex
Full duplex - 18SimplexIn this line data can only travel in one direction. Therefore data can only be sent or recieved. for example, television, radio, computer to printer, address systems and other direction transmissions
- 19Half duplexData can travel in both directions but only one at a time. In other words,data can he sent or recieved at any given time. For example, cb radio and walkie talkie.
- 20Full duplexData can be sent and recieved simultaneously such as telephone convo and video conferencing.
- 21How do you know which channel to choose?1. The amount of info you want to transfer at any given time.
2. A fast or slow transmission rate
3. Whether you want a simplex, half or full duplex channel. - 22What is transmission media?This is the cabled and signalling methods that carries data from one place to another in a network.
- 23Expound on transmission media.Data can be transferred through cabled or wireless media.Cabled media would travel through wires such as the coaxial cable, twisted pair and fibre optic cables. Wireless media travels through the air and involves the use of satellites, microwaves and infrared methods.
- 24Coaxial cableThis has electrical current at radio frequencies and is used in cabled televisions and broadband internet connections.
- 25Fibre optic cableThis contains a bundle of glass fibres that each transmits light. This is mostly used in telephone systems. They are very fast and reliable and transmits data over longer distances than the other cables. The cables are also quite flexible since light beams travel in a straight lines and bounces off the sides of the fibre down its length.
- 26Twisted PairThese are pieces of insulated copper wrapped round each other and are capable of high speed transmission.
- 27What does all wireless transmissions use?Electro-magnetic waves
- 28What determines the frequency of a signal?The number of waves that can be completed in a second.
- 29NBThe shorter the wave the higher the frequency. Radio is low freq
infrared high freq - 30Radio signalsData is transmitted up to a satellite stationary orbit then back down to a recieving station in another country.
- 31Microwave transmissionUses a shorter wave length than radio and can travel up to 50 km. However, it cannot pass through objects or around them.
- 32Infrared transmissionThis cannot go very far and has a very shorter wave length than radio. It is usually used in remotes and domestic devices. The signal also needs a clear space to function appropriately.
- 33Types of infrared used in schools.Line of sight
Scattered infrared communication - 34Line of sightThis means there must be an unblocked direct line between the work station and the tranceiver. Obstructions such as a person breaking the line of sight can slow down the wireless network.
- 35Scattered Infrared CommunicationA broadcast of infrared transmissions that are sent out in multiple directions hitting walls and ceilings bouncing off until it hits the reciever.
- 36Disadvantages of wireless LANs.1. Poor security
2.Susceptible to inferance from light and electronic devices.
3. Slower than LANs cabled links. - 37NBBluetooth and wifi both provide wireless connectivity using radio.
- 38What is WIFI?Wireless Fidelity
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- Flashcards on Data communication , created by Kamarea Lloyd on 22/09/2019.
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- Kamarea Lloyd
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