Acknowledge

Acknowledge mechanism delivery is used in networks communications (series and parallels but also in somes networks protocols), it allows the receiver peripheral to return a signal to transmitter to accept that data were correctly received without errors.

In the case of parallel connections, this function is materialized by a pin on the connector. The connections series use an order in Ascii code, in particular in mode Xon/Xoff  Various protocols networks as the ftp also use this software function. Dane the case of processors, acknowledge is used at the time of the requests for DMA (Direct Memory Access) via a specific pin. When the processor receives a signal of BUSRQ (bus request), it returns via  BUSAK pin an acknowledgement for command, signifing that it's actually disconnected from the data and addresses bus and of order, leaving control to another peripheral.