■Phase 2 with EOT
If the sending station receives an EOT anytime during phase 2, 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
Receiving station
EOT
Occurrence of an error
To phase 3.
■Phase 2 with iterated ENQ transmission due to no response or invalid response
If the sending station receives no response or any invalid response from the receiving station in response to a transmission block sent, it iterates sending of an ENQ at
If the sending station receives an ACK before sending an ENQ nine times, it continues the subsequent message transmission.
Sending station
3seconds
3seconds
Data text m
ENQ
ENQ
Receiving station
ACK
Data text m+1
180
