Appendices
■Abnormal termination of phase 2 (Abort of phase 2)
If the sending station receives no ACK from the receiving station after sending an ENQ nine times in succession, it sends an EOT to the receiving station after 3 seconds from the 9th ENQ to terminate this transmission sequence abnormally.
Sending station
3 seconds
ENQ (1)
3 seconds
ENQ (2)
ENQ (9)
3 seconds
EOT
Abnormal termination
Receiving station
Phase 3: Release of Data Link
■Normal phase 3
The sending station transmits an EOT to the receiving station. Upon receipt of an ACK from the receiving station, the sending station terminates the message trans- mission normally and releases the data link.
Sending station
EOT
Receiving station
ACK
Normal termination
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