What is indicated by the start bit in asynchronous communication?

In asynchronous communication, the start bit plays a crucial role in indicating the beginning of a character transmission. When data is sent without synchronization between the sender and receiver, the start bit signals that a new character is about to be transmitted. This allows the receiving device to recognize the start of the data frame and prepare to interpret the incoming bits that follow.

Asynchronous communication often uses a start bit, followed by the data bits, and typically concludes with one or more stop bits. The presence of the start bit alerts the receiver to switch its state to data-receiving mode, ensuring accurate data interpretation.

This mechanism is essential for distinguishing the transmitted data from idle line signals, thereby facilitating reliable communication between devices.