Help with Alpine Remote Protocol

[mtabo]

Hi, first, thanks for this project, it's just what I needed to get the Sony controller working with the new radio.
If possible I will need a little help to interpret how you assemble the Alpine remote commands (I am trying to change the source button to activate Siri).
The last octet I see that varies for some commands, VolUp, VolDown, Att, TrackUp and TrackDown use 11010101, Source, Off, PstUp and PstDown use 01010101. Why is this?
Thanks in advance.

[deenine]

Thanks for reaching out, unfortunately I cannot find the reference materials I used to create the bit sequences - it was from some forum somewhere. Please let me know if you find any actual protocol specs for an alpine head unit.