Denso BHT-8000 User Manual page 165

Data transmission may accidentally involve various types of errors. The BHT-protocol is designed to
recover from those errors as frequently as possible. What follows is the BHT-protocol for phases 1
through 3.
Phase 1: Establishment of Data Link
Normal phase 1
The sending station transmits an ENQ to the receiving station. Upon receipt of an ACK from the
receiving station, the sending station shifts to phase 2.
Phase 1 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 an ENQ sent, then it iterates sending of an ENQ at three second intervals up to 10 times.
If the sending station receives an ACK before sending an ENQ ten times, it shifts to phase 2.
You may modify the number of ENQ iterations for the sending station. The default is 10 times at
three-second intervals. For details, refer to the SET PROTOCOL screen in System Mode (pp. 58 and
60) and the XFILE statement given in "BHT-BASIC Programmer's Manual."
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Appendices