The method by which data is transmitted character-by-character from the sending computer to the receiving computer is called Asynchronous Transmission . In this case the sender releases a single Start bit on the data cable or media just before the computer transmits the data . The moment the recipient computer detects the presence of the start bit , it turns on its internal clock . This process continues if no stop bit is found from the sender computer. In the asynchronous system, 8-bit character data is transmitted by a start bit in front of it before transmission and at the end by connecting one or two stop bits, each character is converted into 10 or 11 bit data. This method is more useful in environments that require less data transfer, such as the Internet. It does not require any primary storage device from the sender. The interval between transmissions of two consecutive characters is not equal.