Guide: Aeotec Z-Wave Stick - Adding an External Antenna

Thanks and sorry.
One quesetion regarding the Aeotec stick - if appropriate here:
Does the stick hava a dedicated USB <-> serial converter chip or is the conversion idone n the Z-wave chip, that means that the USB data lines are connected directly to the Z-Wave stick?

That technical detail would need to either come from Aeotec or from somebody opening a stick and looking at the chips.