Asynchronous transmission method definition
Asynchronous transmission is the way of transmission when the data or signals are being transmitted and received not synchronously. Asynchronous transmission uses start and stop bits to signify the beginning and ending bits. The method of transmission is deployed when data is sent as packets and not in a solid stream. The start and stop bits have opposite polarity. This allows the receiver to understand when the second packet of information has been sent and send and receive data at their own pace. This mode of transmission is not monitored by the same rate. The specific features of asynchronous transmission are the following: Each character is preceded by a start bit and followed by one or more stop bits and Spaces between characters are common.
Transmission in general is the action of transferring data or signals from one point (component) to another. A letter can be handed to you, received in the mail, read to you or received by via email. In information systems, data transmission is the transferring of data from one system component to another.
Asynchronous method of transmission does not suppose signal timing. Signals are sent in an agreed pattern of bits and if both ends are agreed on the communication pattern. Bits are grouped together and consist of both data and control bits. If the signal is not synchronised the receiver will not be able to distinguish when the next group of bits will arrive.
Because of the increased number of bits and gaps asynchronous method of transmission is quite slow. However, it is effective but cheap form. It is particularly suited for low speed connections. One example of asynchronous transfer is Asynchronous Transfer Mode (ATM) switching which allows voice, data and video to be transmitted in fixed length cells of 53 bytes.