What Is a USB Type-B Connector?

Everything you need to know about the USB Type-B connector

By
Tim Fisher
Photo of Tim Fisher, Lifewire GM and Writer
Tim Fisher
Senior Vice President & Group General Manager, Tech & Sustainability
  • Emporia State University
Tim Fisher has more than 30 years' of professional technology experience. He's been writing about tech for more than two decades and serves as the SVP and General Manager of Lifewire.
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Updated on April 27, 2023

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USB Type-B connectors, officially called Standard-B connectors, are square with slight rounding or large square protrusion on the top, depending on the version.

Apart from USB4, every USB version supports Type-B connectors, including USB 3.0, USB 2.0, and USB 1.1. The second type of "B" connector, called Powered-B, also exists, but only in USB 3.0.

USB 3.0 Type-B connectors are often blue, while USB 2.0 Type-B and USB 1.1 Type-B connectors are often black. That's not always the case because the manufacturer can choose any color for USB Type-B connectors and cables.

A male USB Type-B connector is called a plug, while a female connector is called a receptacle or port.

USB Type-B Uses

Lifewire / Collen Tighe 

USB Type-B receptacles are often on larger computer devices like printers and scanners. Sometimes, you'll find Type-B ports on external storage devices like optical drives, floppy drives, and hard drive enclosures.

Type-B plugs are typically at one end of a USB A/B cable. The USB Type-B plug fits into the Type-B receptacle on the printer or another device, while the USB Type-A plug fits into the type A receptacle located on the host device, like a computer.

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What is USB 3.0?

USB Type-B Compatibility

The Type-B connectors in USB 2.0 and USB 1.1 are identical, meaning that the USB Type-B plug from one USB version will fit into the Type-B receptacle from both its own and the other USB version.

USB 3.0 Type-B connectors are a different shape from previous ones, so the plugs don't fit in those receptacles. However, the USB 3.0 Type-B form factor was designed to allow previous USB Type-B plugs from USB 2.0 and USB 1.1 to fit with USB 3.0 Type-B receptacles.

In other words, USB 1.1 and 2.0 Type-B plugs are physically compatible with USB 3.0 Type-B receptacles, but USB 3.0 Type-B plugs aren't compatible with USB 1.1 or USB 2.0 Type-B receptacles.

USB 3.0 Type-B connectors have nine pins, several more than the four pins found in previous USB Type-B connectors, to allow for a faster USB 3.0 data transfer rate. Those pins had to go somewhere, so the Type-B shape had to be altered somewhat.

There are two USB 3.0 Type-B connectors, USB 3.0 Standard-B and USB 3.0 Powered-B. The plugs and receptacles are identical in shape and follow the outlined physical compatibility rules. However, USB 3.0 Powered-B connectors have two additional pins to provide power, for a total of eleven.

See our USB Physical Compatibility Chart for a graphical representation of physical compatibility, which should help.

The fact that a Type-B connector from one USB version fits in the Type-B connector from another USB version doesn't imply anything about speed or functionality. 

FAQ
  • Are there USB Type-B to USB Type-B cables?

    No, outside of extenders, USB Type-B is almost always paired with another USB connector, usually USB Type-A.

  • Is USB Type-B the best USB standard?

    No. Many devices use different USB connectors based on connector size and reversibility instead of speed.

  • Why isn't USB Type-B as common as other types?

    Size, mostly. The Type-B connector is large compared to, for example, USB Type-C, which you'll more often see on devices today.

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