If your printer supports a printer language (PCL5, ZPL, Esc/P, etc), it should work fine with just about any router/printserver. Although I have not been able to confirm this, I think the QL500 is a host-based printer (i.e.it does NOT support any language). This kind of printer can only be networked by either of the following:
- sharing it from a PC
- connecting it via a printserver that specifically supports the printer.
Asus do not seem to support Brother printers. They do supply printer support lists for their printservers. Click on your model in the list and check.