Asynchronous and Syncronous



The term asynchronous is usually used to describe communications in whichdata can be transmitted intermittently rather than in a steady stream. For example, a telephone conversation is asynchronous because both parties can talk whenever they like. If the communication were synchronous, each party would be required to wait a specified interval before speaking.
The difficulty with asynchronous communications is that the receiver must have a way to distinguish between valid data and noise. In computer communications, this is usually accomplished through a special start bit andstop bit at the beginning and end of each piece of data. For this reason, asynchronous communication is sometimes called start-stop transmission.

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