IF you have the HD version of the 788, yes the AS EC QDE does work with it to give you the Ethernet connection.
The 788ci HD IS the newest version of the 788 models.
The older 788c Combo is not Eternet capable, but can be connected to the OLD 998c and the newest 998c with INTERLINK.
The 998c HD SI Combo is the newest version and discontinued, and the 999ci HD SI Combo is the current 900 series model.
The HD Ethernet port is somewhat hour glass shaped on both the HD versions of the 788c
788c HD Combo
788c HD DI Combo