The current 'variant' of the Edgeport/416, that has the TI chipset, is technically multiple 2-port units bound by a hub chip, so that actually sounds normal to me, regarding the way it's detected. I don't think the hardware is defective, in other words. But you may want to try installing it on a Windows-based computer just for troubleshooting purposes, to ensure that all 16 ports are detected and installed (as COM ports). If all 16 ports "work" under Windows, I suggest bringing this issue up with the Linux community since Digi no longer supports or maintains the Edgeport driver for Linux.