[Win8.1 Universal app] Bixolon R200II Bluetooth communication socket error and strange UUID

So, just for other people's reference - I found the solution.

Turns out the Bixolon R200II has something called "iOS Mode". And as we well know, nothing Mac-ish follows references and requirements. So, when in this mode we get a fake "Serial Port" profile with GUID of . Switching the printer to "Normal mode" yields the standard SPP ("Serial port (SPP) 'Serial Port Profile'") service to appear and be accessible by using "name:serialPort" and "serviceId:00001101-0000-1000-8000-00805f9B34fb" GUIDs.

Case closed :)