Alright, I'm trying to classify this bug report for QEMU. The user mentioned that an Aten USB-to-Serial bridge isn't working under Windows 10 when using QEMU. They're trying to set up serial communication between two machines, one with a native serial port and another using the USB adapter. First, I need to understand what's happening here. The user is using QEMU's serial and chardev parameters but can't get the USB-to-Serial adapter working. However, it works in VirtualBox, so the issue might be specific to QEMU's emulation of USB devices or the serial port handling. Looking at the possible categories: device relates to hardware device emulation, which seems relevant here because the USB-to-Serial bridge is a hardware device that isn't functioning as expected. Other options like 'network' or 'graphic' don't fit since the problem is specifically with the serial and USB devices. I recall that QEMU emulates various hardware devices, including USB controllers and serial ports. If the user's setup works in VirtualBox but not QEMU, it might be a bug in how QEMU handles the USB-to-Serial bridge. This falls under device emulation issues rather than other categories like performance or kernel issues. So, the most appropriate category for this bug is 'device' because it pertains to the proper functioning of the USB-to-Serial adapter within the emulated environment provided by QEMU. The issue revolves around a hardware device (USB-to-Serial bridge) not functioning correctly under QEMU. Since VirtualBox works fine, it's likely a problem with QEMU's device emulation. **device**