So, which slicer CAN really print by USB rather than using a IMHO crappy solution with these micro SD cards - after some 10-12 prints the slot in my Tronxy X5SA pro was MIA, card not holding, contacts not reacting. New board (still under warranty) hopefully will be underway soon.
On my old and trusty Dremel 3D20 (4700 hours!) I could print by USB, either with the slicer they provided, or with Print Studio. This printer has a micro SD card onboard, but not to be touched by the user (unless you had to change the controller board for some reason and wanted to keep the firmware and settings). This SD card was an ideal solution, with 8GB more than enough for firmware AND files. No changing of cards (in this case real full size SD cards wwhich have a lifetime of an elephant), just dump your sliced data there, and print them whenever you wanted. And there was a REAL SD card slot too!
Why can't other producers follow this example? Price? Yes, every cent counts, but the users WILL pay if they can get this comfort.
So, back to my question - does S3D support printing by USB? Every other solution (server, Wifi, cloud etc) I do not need - my dedicated micro PC resides INSIDE the frame of the printer.
Well, by reading on another forum I found an answer - my firmware (Tronxy X5SA pro, board by Chitu) has a lot of issues - among others with USB - which can only be solved by installing something better. Interestingly, their own slicer DOES work by USB (a rather simplified older Cura-version). (headscratch)
So, back to the start. If it has to be an external memory, then I'll use an SD card adapter and send the sliced data to a Toshiba Flashair w03 - don't try to get one - they are no longer available.