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Handshaking for asynchronous data transfer


For data transfer between two computers, the sending and receiving speeds on both ends are often different. Therefore, a mechanism is needed to make sure that the sender does not send a new byte before the previously sent byte is received by the receiver. Even when the sender and receiver operate at the same speed, the sender may still want to know whether the receiver has indeed received the information. Handshaking provides a mechanism for addressing this issue. Handshaking usually uses two additional hardware lines, one is called “strobe” and the other is called “acknowledge”. The sender provides the signal to the strobe line and the receiver provides the signal to the acknowledge line.

Handshaking can be used in both parallel data transfer and serial data transfer.

We will study four different data transfer conventions: simple output, simple strobe, single hand shaking and double handshaking.