Acknowledge character

In telecommunications, an acknowledge character (ACK) is a transmission control character transmitted by the receiving station as an acknowledgement, i.e. an affirmative response to the sending station, perhaps in response to the sending station's transmission of an ENQ.

Binary Synchronous Communications does not use a single ACK character, but has two control sequences for alternate even/odd block acknowledgement.

In the ASCII code, the ACK character is 6 (decimal), or ^F. Unicode also provides a visible representation at U+2406(␆).

"ACK" is also used as a slang abbreviation in internet forums and chats (mainly technology) for "Understood/Accepted".

See also

• Enquiry character
• Negative-acknowledge character
• C0 and C1 control codes

References

•  This article incorporates public domain material from Federal Standard 1037C. General Services Administration. Archived from the original on 2022-01-22. (in support of MIL-STD-188).