Synchronous and asynchronous transmission

All forms of data transmission require a sender and a receiver.

In order for transmission to be successful, the two devices must be synchronised – that is, they both need to know when to expect data, and at what rate.

Synchronous data transmission is used where the volume of data is anything but tiny; both the sender and receiver are in sync with each other, and data is transmitted in blocks.

Asynchronous transmission is used where the volume of data is very small, and transmits in individual bytes. The sender and receiver only need to synchronise with each other during the transmission process, rather than continually as in synchronous transfer.

Comparison

Asynchronous transfer is ideal for very low data volumes, and is also ideal where power budgets are slim; not needing to maintain synchronisation between the sender and receiver at all times hugely reduces the power requirements.

Synchronous transmission is far more suited where speed of transmission and volume of information is greater.