96
EOT
3 seconds
3 seconds
ENQ
ENQ
ACK
■ 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 the phase 3 terminates
normally, the transmission results in an abnormal end.
Sending
station
Receiving
station
To phase 3.
Occurrence of
an error
■ 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 three-second intervals up to nine times.
If the sending station receives an ACK before sending an ENQ nine times, it
continues the subsequent message transmission.
Sending
station
Receiving
station
Data text m
Data text m+1