The USB port on the RW series of mobile printers is intended for setup and maintenance of the printer. For wired communications, Zebra recommends using a serial RJ-45 cable for connection with your RW printer's RS-232C serial port. This USB to RJ-45 cable allows a twist-lock strain relief mechanism to protect your cable and the port on your printer. It uses USB protocol to send the data to your printer from a USB host device via the RJ-45 serial port.