ACK (signal)
An ACK signal (from English acknowledgment , in technical context 'acknowledgment of receipt', 'acknowledgment') is a signal that is used during data transmission to confirm the receipt or processing of data or commands.
General
In character sets for controlling terminals , ACK often exists as a control character ( ASCII 06, EBCDIC 46), in network protocols special data packets can have the meaning ACK.
The rejection of transmitted data ( e.g. due to incorrect reception) is often acknowledged in this context with NAK ( N o A c k nowledgement / N egative A c k nowledgement) or NACK , for example with ASCII code 21 (CTRL-U ). In such a case, an attempt is usually made to retransmit the data or the connection is terminated with an error.
Examples of protocols that use ACK signals in various forms are TCP and DHCP . An ACK message is also used when changing DNS entries using the connectivity coordination (KK) method when changing providers.
Network jargon
Derived from this meaning in data transmission, ACK is used in network jargon as consent , in the sense of “exactly, that's how it is”, or “I agree” or “that's ok”.