Automatic Repeat Request

Automatic Repeat-reQuest (ARQ) is an error control method for data transmission which uses acknowledgments and timeouts to achieve reliable data transmission. An acknowledgment is a message sent by the receiver to the transmitter to indicate that it has correctly received a data frame. A timeout is a reasonable point in time after the sender sends the data frame; if the sender does not receive an acknowledgment before the timeout, it usually re-transmits the frame until it receives an acknowledgment or exceeds a predefined number of re-transmissions.
See more at Wikipedia.org...

See ARQ.

<communications> (ARQ) A modem error control protocol in which the receiver asks the transmitter to resend corrupted data.
(1995-11-14)