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Chapter 3. Communications Operations of BHT-5000
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Phase 2 with NAK
If the sending station receives a NAK 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 an ACK before receiving a NAK 10 times in succes-
sion, it continues the subsequent message transmission.
NAK
NAK
ACK
NAK
NAK
NAK
(1)
(2)
(10)
Sending
station
Receiving
station
Data text m
Data text m
Data text m
Data text m+1
If the sending station receives a NAK 10 times in succession or it fails to send a
same transmission block, it shifts to phase 3 to terminate the message transmis-
sion abnormally. Even if the phase 3 terminates normally, the transmission results
in an abnormal end.
Sending
station
Receiving
station
Data text m
Data text m
Data text m
To phase 3.
Occurrence
of an error
