USB-B is the somewhat square, slightly domed connector that was common on the peripheral end of USB cables in the early years of USB. While a USB-A plug went into the computer, a USB-B plug went into the device itself.
Typical USB-B devices included printers, scanners and external hard drive enclosures. A smaller variant, USB-B Micro, was later used on some external hard drives and early Android phones before micro-USB and then USB-C took over. USB-B never appeared on the same range of small, mobile devices as micro-USB or mini-USB, since its size made it impractical for compact gadgets.
Today USB-B has largely disappeared from new products, replaced first by micro-USB and mini-USB and now almost entirely by USB-C. It is still worth recognising if you come across older printers or audio interfaces, since a printer cable is one of the few places a standard USB-B port survives. See the connector overview for the full family of USB plugs.
