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In synchronous transmission, data moves in a complete paired approach in the form of chunks or frames. Synchronisation between the source and target is required so that the source knows where the new byte begins since there is no space between the data.
Synchronous transmission is effective, dependable and is utilised for transmitting a large amount of data. It offers real-time communication between linked devices.
A comparison of synchronous transmission would be the transfer of a large text file. Before the file is transmitted, it is first dissected into blocks of sentences. The blocks are then transferred over the communication link to the target location.
Because there is no beginning and end bits the data transfer rate is quicker but there’s a possibility of more errors to occur. Over time, clocks will get out of sync and the target device would have the incorrect time, so some bytes could become tampered due to lost bits. To resolve this issue, there is a need for regular re-synchronisation of the clocks as well as the use of check digits to make sure that the bytes are correctly received and translated.
Characteristics of Synchronous Transmission
- There are no spaces in between characters being sent.
- Timing is provided by modems or other devices at the end of the transmission.
- Special syn characters goes before the data being sent.
- The syn characters are applied between chunks of data for timing functions.
Examples of Synchronous Transmission
- Video conferencing
- Telephonic conversations
- Face-to-face interactions
In asynchronous transmission data moves in a half-paired approach, 1 byte or 1 character at a time. It sends the data in a constant current of bytes. The size of a character transmitted is 8 bits where a parity bit is added each at the beginning and at the end which makes it a total of 10 bits. It doesn’t need a clock for integration; rather it utilises the parity bits to inform the receiver how to translate the data.
It is straightforward, quick, cost-effective and doesn’t need a 2-way communication.
Characteristics of Asynchronous Transmission
- Each character is headed by a beginning bit and superseded by one or more end bits.
- There may be gaps or spaces in between characters.
Examples of Asynchronous Transmission
Synchronous and Asynchronous Transmission
|Point of Comparison||Synchronous Transmission||Asynchronous Transmission|
|Definition||Transmits data in the form of chunks or frames||Transmits 1 byte or character at a time|
|Speed of Transmission||Quick||Slow|
|With gap between the data?||Yes||None|
|Examples||Chat Rooms, Telephonic Conversations, Video Conferencing||Email, Forums, Letters|
Synchronous vs. Asynchronous Transmission
- In synchronous transmission data is transmitted in the form of chunks, while in asynchronous transmission data is transmitted one byte at a time.
- Synchronous transmission needs a clock signal between the source and target to let the target know of the new byte. While in asynchronous transmission, a clock signal is not needed because of the parity bit attached to the data sent which serves as a start indicator of the new byte.
- Data transfer rate of synchronous transmission is faster since it transmits in chunks of data, compared to asynchronous transmission which transmits one byte at a time.
- Asynchronous transmission is straightforward and cost-effective while synchronous transmission is complicated and pricey.
- Synchronous transmission is systematic and needs lower overhead compared to asynchronous transmission.
Both synchronous and asynchronous transmission have their benefits and limitations. Asynchronous is used for sending a small amount of data while synchronous transmission is used for sending bulk of data. Therefore, that both synchronous and asynchronous transmissions are essential for data transmission.