Casio CTK-691 Midi Implementation Manual page 41

In the case of the WK-3500, for example, when a communication request is received from an external source
while floppy disk control is being performed, BSY is returned to an external device that sends BDS, BDR, HDS,
HDR.
When the BSY is received, the receiver must wait until this Model enters a session-enabled mode, or use a
Prepare for Data Management parameter (see "20.2 Data Management Command List") to change to a
communication-enabled mode.
Data Receiver
BDR →
← BSY
Data Receiver
BDS →
← BSY
Data Receiver
HDR →
← BSY
Data Receiver
HDS →
← BSY
The same packet is resent when a checksum mismatch or incompatible data structure error is detected.
Data Sender
(Send Canceled)
Data Sender
(Send Canceled)
Data Sender
(Send Canceled)
Data Sender
(Send Canceled)
Operation
Send Request
Busy
Operation
Data Send
Busy
Operation
Send Request
Busy
Operation
Data Send
Busy
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