They are used to add USB 2.0 ports to a computer that was not originally equipped with them.
You need to get a wireless adapter for that, either external such as USB, or internal such as PCI, PCI-E and so on.
You can use USB video card, but it might even slower than PCI.
As of now, probably USB 3.1, at least until the introduction of the USB Type-C connector that will allow communications from different buses to be used (USB 3.x, Thunderbolt, PCI Express).
Acts just like a modem that you would plug into a PCI slot but it's external and portable and you can simply plug it into a USB slot onto your computer.
A USB PCI card can be purchased from many different stores and retailers. Some examples that sell USB PCI cards include Dell, Newegg, CDW, and Walmart.
An external USB hard drive can be used for several purposes. It can add additional storage space to your computer or laptop. It is also great for recovering damaged information on a computer.
PCI Express bus standard or the USB 2.0 standard
One way to add USB ports to a computer you need a USB expansion card that you add to the motherboard. The card usually has multiple USB ports built into them.
firewire and usb
Typically it is a usb port 2.0.
Almost any USB wireless adapter, and depending on model you can use also PCI mini cards.
Usb port