A digital protocol implements automatic repeat request (ARQ). What does it permit?

Automatic Repeat Request (ARQ) is an error-control method used in many digital protocols. When the receiving station detects that a packet of data contains errors, it automatically requests the transmitting station to resend that specific packet. Because the protocol actively replaces corrupted data with a fresh, accurate copy, it serves as a highly effective form of error correction. This ensures a flawless final message, which is essential for text-based digital modes like packet radio or AMTOR. While ARQ relies on 'error detection' to know when to ask for a resend, the ARQ process itself provides 'error correction' by fixing the missing or bad data. It does not provide automatic link establishment, nor does it inherently authorize unattended operation.