Sending the character "I" to the Wattson when it is in Power collecting mode (3996W in display - the W is the power indicator)

This corresponds perfectly to the "p0F9C" - which in decimal is 3996.

So the Wattson is now reporting every point it is collecting - excellent.

I now think I may have a starting point for interfacing the Wattson and starting to collect my own data.