Data Tansmission is the process of transferring data between two or more digitally connected devices . Data is transmitted from one device to another in analog or digital format . Transmission of Data occur in Binary bit i.e. 0 or 1 .
Types Of Data Transmission :-
Basically there are two types of data transmission :-
1.Parallel Data Transmission
2.Serial Data Transmission
Fig. Types Of Data Transmission
1.Parallel Data Transmission :-
When transmission of data between digital devices occur in group then this transmission is called as Parallel Data Transmission . For transmitting data single wire is used for transmitting single bit e.g. if 8 bit is needed to send then 8 wires will be used to transmit data .
Speed of transmitting data in parallel transmission is faster than that of Serial transmission , but Parallel transmission is expensive than that of serial transmission because it uses more wire to transmit data and there is no full utilization of transmission media .
e.g. this was used in old computer devices like printer, hard disk drive but now a days serial transmission is used in this .
Fig. Parallel Transmission .
2.Serial Data Transmission :-
When the transmission occur between devices of computer bit-by-bit i.e. when transmission of data occur bit-by-bit through single wire then this type of transmission is called as Serial Data Transmission .
Fig. Serial Transmission
Serial Transmission is cheaper than that of Parallel Data Transmission . Now a days this technology is used to transmit data . By using this transmission method there is full utilization of Transmission Media .
Further there are two modes of Data Transmission under Serial Data Transmission :-
a)Synchronous Serial Transmission
b)Asynchronous Serial Transmission
2.a)Synchronous Serial Transmission :-
Data bits are transmitted as a continuous stream in time with a master clock. The data transmitter and receiver both operate using a synchronized clock frequency; therefore, start bits, stop bits, and gaps are not used. This means that data moves faster and timing errors are less frequent because the transmitter and receiver time is synced. However, data accuracy is highly dependent on timing being synced correctly between devices. In comparison with asynchronous serial transmission, this method is usually more expensive.
Fig . Synchronous Serial Transmission
2.b)Asynchronous Data Transmission :-
Data bits can be sent at any point in time. Stop bits and start bits are used between data bytes to synchronize the transmitter and receiver and to ensure that the data is transmitted correctly. The time between sending and receiving data bits is not constant, so gaps are used to provide time between transmissions.
The advantage of using the asynchronous method is that no synchronization is required between the transmitter and receiver devices. It is also a more cost effective method. A disadvantage is that data transmission can be slower, but this is not always the case.
Fig . Asynchronous Serial Transmission
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