In this final section, we will use a printer as an example to describe the requirements for USB-compliant devices. First, let's take a look at an outline of a legacy printer.


Outline of a legacy printer


If we were to add an USB interface without changing the system on the printer, we will need to develop a bridge.


Development of the bridge


As you can see, even a bridge for conversion to and from a USB interface will at the least require the development of a driver, firmware, and USB endpoints with controlling circuits.