HP Forums

I'm looking at the Sharp SSIO protocol and can't quite understand how it is supposed to work. In the PCG850VS users guide by Jack W. Hsu there is a diagram showing the output on the 11 pin interface signals for LPRINT "X". The bit I'm having trouble understanding is why the data line doesn't show the serial wiggles for hexadecimal 58 which is ASCII X.
There also seem to be four characters sent (XOUT goes high four times) which doesn't seem to match LPRINT "X", even if a CR,LF is sent as well as the X.

Anyone have any experience of this protocol or any idea what is going on?

Part of the confusion may be due to the fact that the data logic level is inverted (low = '1')