149
Appendices

■ Phase 2 with a sequence of DLE EOT and IDs

If the sending station receives a sequence of DLE EOT and IDs 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.
DLE EOT and IDs
Occurrence of
an error

■ Phase 2 with iterated transmission of DLE ENQ and IDs 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 a
sequence of DLE ENQ and IDs at 0.5-second intervals up to 59 times.
If the sending station receives a sequence of DLE ACK and IDs before sending the
sequence of DLE ENQ and IDs 59 times, it continues the subsequent message
transmission.
Sending
station
Receiving
station
Data text m
Data text m+1
DLE ENQ and IDs
DLE ACK and IDs
DLE ENQ and IDs
0.5 second
0.5 second