DS9808 directIO image capture

Hi folks,

 

I'm writing a JPOS application to interface with the DS9808 and I'm wondering what the best way to send a directIO message to the scanner to trigger an image capture.

 

I've got the attribute data dictionary and I see 647 and 648 for Snapshot by Motion and Continuous Snapshot neither of these seems to do anything when I flip the value on and off.

 

Ideally, I just want to send an opcode to the scanner telling it to capture an image. How is the best way to do that?