USB port or USB connector
I wouldn't use USB interface here. I found this useful info on How Stuff Works:
"Just about any computer that you buy for your home or office today comes with one or more Universal Serial Bus connectors on the back. These USB connectors let you attach everything from mice to printers to your computer quickly and easily. The operating system supports USB as well, so the installation of the device drivers is quick and easy too. Compared to other ways of connecting devices to your computer (including parallel ports, serial ports and special cards that you install inside the computer's case), USB devices are incredibly simple!
In this edition of How Stuff Works, we will look at USB ports from both a user and a technical standpoint. You will learn why the USB system is so flexible, and why USB is able to support so many devices so easily -- it truly is an amazing system! "