| What is data transmission? | Sending data from one location to another |
| What are the factors considered in data transmission? | Direction
Method
Synchronization |
| What are the different directions in data transmission? | Simplex
Data flows in one direction
Ex: Television broadcast
Half duplex
Data flows in both directions one at a time
Walkie talkie
Full duplex
Data flows in both directions simultaneously
Telephone |
| What are the methods of data transmission ? | Serial transmission
When bits travel along a single wire/data channel one at a time
Parallel transmission
Multiple bits travel simultaneously on different wires/data channels |
| What are the advantages of serial transmission ? | Can transmit longer distances
Cheap technology |
| What are the disadvantages of serial transmission ? | Slower |
| What are the applications of serial transmission? | USB(Universal Serial Bus)
Transmission of data n LAN |
| What are advantages of Parallel transmission? | Faster |
| What are the disadvantages of Parallel transmission? | More expensive
Can transmit shorter distances |
| What are the synchronizations in data transmission? | Synchronous
Asynchronous |
| What is synchronous transmission? | Data is transmitted at a constant rate in a continuous stream
Both computers must work at same speed
Before transmission two extra bits are sent(timing signals). These inform the receiving computer at what speed transmission is done |
| What is asynchronous transmission? | Data is transmitted in separate blocks
Each block is accompanied by a start bit and a stop bit, which inform the receiver that there is incoming data and complete block has been received |
| What is the advantage and disadvantage of synchronous transmission? | Fast
Timing must be very accurate so it is expensive |
| What is the advantage and disadvantage of asynchronous transmission? | Cheaper as timing isn't important
Slower |
| Why is parallel transmission over a long distance not possible? | Due to SKEW an error which occurs in parallel transmission where bits change speed during transmission and are not received simultaneously |
| What are the features of a USB(Universal Serial Bus)? | Uses serial, asynchronous transmission
Method of connecting devices
4 wires are used in USB
2 wires for transmitting data either direction
1 wire for charging
1wire(earth) to prevent electrocution |
| State three devices that use USB connection? | Laptop
Pen drive
Phone |
| Give 6 advantages of USB connection | 1) Can be connected in such a way that that minimizes the risk of damaging the devices due to incorrect connection
2)When you connect the device, it is automatically detected, and the device diver is loaded for it
3)Can connect to a wide variety of devices
4)As the technology is so popular the user has a lot of after sales support
5)USB supports several different transmission speed
6)Backward compatibility(Devices with newer USB technologies can still work with older technologies) |
| Give 3 disadvantages of USB connection | 1)Maximum cable length is short distance
2)The USB is slow in speed
3)Older USB standard may not be supported in the near future |
| What is IP address ? | A unique number given to each device connected to the internet
It consists of four groups of up to 3 digit number, and 255 being the largest number of one group
Each IP address is 32 bits
IP address is given by ISP |
| What is a URL and what are the parts of a URL? | A unique address given to each website
Protocol
Name of website/domain
Name of webpage |
| What is a protocol? | A set of rules that must be followed when communicating with another device |
| What is a web browser? | A program that allows user to access webpages |
| What is a search engine ? | Allows the user to search for webpages that contains a word or phrase the user needs |
