Calibre on a MacBook Pro (late 2016, TB)

I have a new MBP (late 2016, TB) which only has USB-C. I attached my PocketBook Touch Lux 3 using an adapter (USB-C to USB-A). When I attach the reader it doesn't ask whether to use the PC Link or Charge, so I guess the PocketBook may be the problem. Calibre doesn't seem to see the device either.
I tried to activate the PC Link manually but that doesn't seem to help since nothing happens.
Any advice on how to proceed with this?

Thanks in advance,
erich.