■Phase 2 with a sequence of DLE NAK and IDs
If the sending station receives a sequence of DLE NAK and IDs from the receiving station in response to a transmission block containing text data m, it sends that transmission block again immediately as shown below.
If the sending station receives a sequence of DLE ACK and IDs before receiving the sequence of DLE NAK and IDs 10 times in succession, it continues the subsequent message transmission.
Sending station
Data text m
Receiving station
DLE NAK and IDs
Data text m
DLE NAK and IDs
Data text m
DLE ACK and IDs
Data text m+1
If the sending station receives a sequence of DLE NAK and IDs 10 times in succes- sion or it fails to send a same transmission block, it shifts to phase 3 to terminate the message transmission abnormally. Even if phase 3 terminates normally, the transmission results in an abnormal end.
Sending station
Data text m(1)
Receiving station
DLE NAK and IDs
Data text m(2)
DLE NAK and IDs
Data text m(10)
DLE NAK and IDs
Occurrence of an error
To phase 3.
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