I wanted to use my raspberry pi as USB bridge between multiple devices. We can assume that I want to connect my iPad which has POS software on it to my thermal printer. Most of star or Epson thermal printers can be recognized by iOS since they have MFi certification( It doesn't mean they have to be AirPrint compatible because they are not, they can be detected when they will be connected to iOS by lightening cable.). I want to put my Raspberry Pi in the middle and act as they cannot see there is a device between them so technically iOS will detect printer as usual. In this case, I wanted to use USB monitoring packages to see what is happening between iPad and printer in terms of transferring data. I would be very happy if you can share your experience and ideas on this subject.