Thanks buzz and Jared for your answers. I now realise that i didnt communicatie clearly enough. Let's clear it up:
From previous test (e.g. with PHD + Cartes-du-Ciel) I know that the Ascom driver of my mount (MTS-3 driver for Vixen GP) cannot accept simultaneous connections from more than one application.
Using the Ascom POTH Hub was sort of a solution but it was critical with the order in which to connect the various components. So I prefer not to use the POTH hub.
Now with SGP i am hopefull that all components that need to talk to the mount driver (PHD, Goto-command from SGP, maybe a handcontroller) do that through SGP, not directly. That way, I wouldn't need the POTH. What do you think?
I called that a hub functionality because SGP would need to combine the signals from PHD and its own Goto command, but that is not a proper term I guess.
So I don't want to connect CDC + SGP to my Ascom driver, just SGP.