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Solution:
Data Transfer:
Data refers to groups of bits that convey some type of information.
Binary data, which are represented by digital waveforms, must be transferred from one device to another within a digital system or from one system to another in order to accomplish a given purpose.
For example, numbers stored in binary form in the memory of a computer must be transferred to the computer’s central processing unit in order to be added.
The sum of the addition must then be transferred to a monitor for display and/or transferred back to the memory.
As illustrated in Figure, binary data are transferred in two ways: serial and parallel.
(a) Serial transfer of 8 bits of binary data:
When bits are transferred in serial form from one point to another, they are sent one bit at a time along a single line, as illustrated in Figure(a).
During the time interval from t0 to t1 , the first bit is transferred. During the time interval from t1 to t2 , the second bit is transferred, and so on.
To transfer eight bits in series, it takes eight time intervals.
(b) Parallel transfer of 8 bits of binary data:
When bits are transferred in parallel form, all the bits in a group are sent out on separate lines at the same time.
There is one line for each bit, as shown in Figure (b) for the example of eight bits being transferred.
-To transfer eight bits in parallel, it takes one-time interval compared to eight time intervals for the serial transfer.
To summarize, an advantage of serial transfer of binary data is that a minimum of only one line is required.
In parallel transfer, a number of lines equal to the number of bits to be transferred at one time is required.
A disadvantage of serial transfer is that it takes longer to transfer a given number of bits than with parallel transfer at the same clock frequency.
For example, if one bit can be transferred in 1 ms, then it takes 8 ms to serially transfer eight bits but only 1 ms to parallel transfer eight bits.