Read all the posts on the page to get the picture. Bit technical but very interesting.
https://www.rcgroups.com/forums/showthread.php?1773138-Lemon-DSM2-DSMX-Compatible-Receivers/page843
https://www.rcgroups.com/forums/showthread.php?1773138-Lemon-DSM2-DSMX-Compatible-Receivers/page843