mwijas,

sorry i did not see your reply!
wel i didn't have time to work on that, maybe in the coming weeks...
I'm using Iviewer (command fusion), this give me the possibility to use javasrcipt to calculate the checksum. But i'm nowhere in JS, so still have to work on it.
Besides I don't understand the feedbacks (response) of the sony wel, with those bytes...

I don't have the toggle code for mute and power. why would you want to use that?
discrete is much beter..