Asynchronous transmission is a type of data transmission in which data travels one byte or character at a time without using a clock signal to synchronize the timing between the sender and receiver. Instead, each character is preceded by a start bit and followed by a stop bit, which marks the beginning and end of the character. Asynchronous transmission is often used in applications where data is transmitted in small amounts, and timing constraints are not critical i.e., USB or Bluetooth. It is a simple and flexible method of communication that can be easily implemented using basic hardware and software. Asynchronous transmission is slower than synchronous transmission (which uses a clock signal to synchronize the transmission), but it can accommodate a wider range of transmission speeds and data formats.