Transmission of data
Data is transferred between devices in two ways: serial transmission and parallel transmission. - Parallel transmission is the transmission of data simultaneously using separate channels.
- Serial transmission is the transmission of data one after the other.
- Serial transmission is used to transmit data to peripheral devices, such as modems and printers, and is used on networks.
Serial transmission can be either synchronous or asynchronous. - Asynchronous transmission is the sending of data by identifying each byte with special start and stop bits.
- It has become the standard for personal computers.
- Part of protocol agreement is to specify how many start and stop bits.
- The normal range is between 0 and 2.
- Synchronous transmission requires all the data to be sent at the same rate. The same number of bytes is sent each second. This is synchronised by each device using a clock.
- Synchronous transmission is faster and more efficient than asynchronous transmission as there are no extra bits. It is used on larger computer systems.
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