Asynchronous serial data transfer
In most computer asynchronous mode of data transfer is used in which two component have a different clock. Data transfer can occur between data in two ways serial and parallel. In case of parallel multiple lines are used to send a single bit whereas in serial transfer each bit is send one at a time. To tell other devices when the character/data will be given a concept of start and end bit is used. A start bit is denoted by 0 and stop bit is detected when line return to 1-state at least one time, here 1-state means that there is no data transfer is occurring.
When a character is not being sent then line is kept in state 1. Start of character is detected when a 0 is sent. The character bit always come after 0 bit. After last bit is sent the state of line to become 1.
The diagram below shows this concept:
Here earlier state of line was 1 when a character has to be send a 0 is send and character bit are transferred.
Difference between serial and parallel transfer –
|Require single line to send data||Require multiple line|
|Less error and simple model||Error prone and complex working|
|Slower data transfer||Faster data transfer|
|Used for long distance||used for short distance|
|Example:Computer to Computer||Example:Computer to Printer|