The ARQ reference article from the English Wikipedia on 24-Apr-2004
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ARQ

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ARQ is an acronym for Automatic Repeat-reQuest. Error control for data transmission in which the receiver detects transmission errors in a message and automatically requests a retransmission from the transmitter.

Usually, when the transmitter receives the ARQ, the transmitter retransmits the message until it is either correctly received or the error persists beyond a predetermined number of retransmissions.