Ai-net was always designed to daisy chain.
The 9856 must have been the first iteration of the KCE-422i cable. It's the same cable necessary for the 9887. THe 9855 utilized the KCA-420i. If you want to use anything beyond a 5th generation iPod you need an adapter that crosses the firewire pin outs as well as reducing it to 5V so that your item can charge. Otherwise, your ipod will play and function, it just won't charge. iPhone can't be controlled though.
KCE-422i
KCX-422tr
KCA-420i