Normal phase 1 – Denso BHT-6000 User Manual

Page 123

108

Data transmission may accidentally involve various types of errors. The BHT-Ir proto-
col is designed to recover from those errors as frequently as possible. What follows is
the BHT-Ir protocol for phases 1 through 3.

Phase 1: Establishment of Data Link

■

Normal phase 1

The sending station transmits a sequence of DLE ENQ and IDm (sending station’s
ID) to the receiving station. Upon receipt of a sequence of DLE ACK and IDs
(receiving station’s ID) from the receiving station, the sending station shifts to
phase 2.

To phase 2.

Receiving station

Sending station

■

Phase 1 with iterated transmission of DLE ENQ and IDm due to no re-

sponse or invalid response

If the sending station receives no response or any invalid response from the
receiving station in response to the sent sequence of DLE ENQ and IDm, it iterates
sending of the sequence at 0.5-second intervals up to 60 times.

If the sending station receives a sequence of DLE ACK and IDs before sending the
sequence of DLE ENQ and IDm 60 times, it shifts to phase 2.

DLE ENQ and IDm

DLE ACK and IDs

Sending
station

Receiving
station

To phase 2.

DLE ENQ and IDm

DLE ACK and IDs

0.5 second

TIP

You may modify the number of iterations of a sequence of DLE ENQ and IDm
for the sending station. The default is 60 times at 0.5-second intervals. For
details, refer to the SET LINKUP TIME screen in System Mode (p. 51) and the
XFILE statement given in "BHT-BASIC 3.0 Programmer’s Manual."