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■ 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
Receiving
station
Data text m
Data text m
Data text m
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 the phase 3 terminates normally,
the transmission results in an abnormal end.
Sending
station
Receiving
station
Data text m(10)
Data text m(2)
Data text m(1)
DLE NAK and IDs
DLE NAK and IDs
DLE ACK and IDs
DLE NAK and IDs
DLE NAK and IDs
DLE NAK and IDs
Occurrence
of an error
To phase 3.