# USB 3 Standard-B plug

> a legacy USB plug that preceded USB-C (“B” indicating the peripheral device end)

**Wikidata**: [Q133458629](https://www.wikidata.org/wiki/Q133458629)  
**Source**: https://4ort.xyz/entity/usb-3-standard-b-plug

## Summary
The USB 3 Standard-B plug is a legacy USB plug designed for the peripheral device end, which preceded the introduction of USB-C. It is officially known as the USB 3.1 Standard-B plug and was developed by the USB Implementers Forum. This plug type is distinct from host-side connectors and was commonly used for connecting USB 3.x peripheral devices.

## Key Facts
- The official name for this entity is the USB 3.1 Standard-B plug.
- It is a legacy USB plug that was replaced by the USB-C plug.
- The "B" in its name indicates it is designed for the peripheral device end of a connection.
- It is an instance of a USB 3 Standard-B connector, USB 3 Standard Type-B plug, and a general USB Standard-B plug.
- This plug connects with a USB 3 Standard-B receptacle or a USB Powered-B receptacle.
- It features a 9-pin configuration for data transfer and power delivery.
- The standards body responsible for its specification is the USB Implementers Forum.
- Aliases include USB 10Gbps Standard-B plug, SuperSpeed+ USB Standard-B plug, and USB 5Gbps Standard-B plug.
- An image of the plug is available at `https://commons.wikimedia.org/wiki/Special:FilePath/USB_connector_illustration,_to_scale,_front_view,_legacy,_USB_3_Standard-B_plug.svg`.

## FAQs
### Q: What is a USB 3 Standard-B plug?
A: The USB 3 Standard-B plug is a legacy USB plug designed for the peripheral device end of a connection. It was developed as part of the USB 3.x standard and was later superseded by the USB-C plug.

### Q: What does the "B" in USB 3 Standard-B plug signify?
A: The "B" in USB 3 Standard-B plug indicates that it is designed for the peripheral device end of a USB connection. This differentiates it from "A" type plugs, which are typically found on the host side.

### Q: What replaced the USB 3 Standard-B plug?
A: The USB 3 Standard-B plug was replaced by the USB-C plug. USB-C offers a reversible design and supports higher data transfer rates and power delivery capabilities.

### Q: How many pins does a USB 3 Standard-B plug have?
A: A USB 3 Standard-B plug has 9 pins. These pins facilitate both power delivery and SuperSpeed data transfer capabilities.

### Q: What is the official name for the USB 3 Standard-B plug?
A: The official name for this plug, according to the USB Implementers Forum, is the USB 3.1 Standard-B plug.

## Why It Matters
The USB 3 Standard-B plug played a crucial role in the evolution of Universal Serial Bus technology, particularly during the transition to higher data transfer speeds offered by USB 3.x. As a dedicated peripheral-side connector, it enabled devices like external hard drives, printers, and docking stations to leverage the enhanced performance of USB 3.0 and later iterations before the widespread adoption of USB-C. Its distinct physical design, incorporating additional pins for SuperSpeed data, was a clear indicator of its advanced capabilities over its USB 2.0 predecessor. The existence of the "B" type connector helped maintain a clear distinction between host and device ends, preventing incorrect connections in earlier USB ecosystems. While now considered a legacy component, its development paved the way for the more versatile and universal USB-C standard, demonstrating the continuous drive for improved connectivity solutions. Its presence in countless devices solidified USB 3.x as a dominant interface for several years, impacting how users connected and transferred data with their peripherals.

## Notable For
- Being a legacy USB plug specifically designed for the peripheral device end, distinct from host-side connectors.
- Preceding the universal and reversible USB-C plug as the standard for peripheral connections.
- Featuring a unique physical design that visually differentiates it from USB 3 Standard-A and USB 3 Micro-B plugs.
- Incorporating additional pins (9 total) to support SuperSpeed data transfer capabilities, distinguishing it from USB 2.0 B-type plugs.
- Being officially designated as the USB 3.1 Standard-B plug by the USB Implementers Forum.

## Body

### Overview
The USB 3 Standard-B plug is a type of legacy Universal Serial Bus (USB) plug. It is specifically designed for the peripheral device end of a USB connection, indicated by the "B" in its name. This plug type preceded the development and widespread adoption of the USB-C plug. Its function was to connect USB 3.x compatible peripheral devices to a host.

### Classification and Relationships
The USB 3 Standard-B plug is classified as:
- An instance of a USB 3 Standard-B connector.
- An instance of a USB 3 Standard Type-B plug.
- An instance of a USB Standard-B plug.

It is related to:
- USB Standard-B plug (class)
- USB 3 Standard-B connector (class)
- USB 3 Standard Type-B plug (class)

This plug is the opposite of a USB 3 Standard-B receptacle. It is designed to connect with:
- USB 3 Standard-B receptacle
- USB Powered-B receptacle

The USB 3 Standard-B plug is different from:
- USB Powered-B plug
- USB 3 Standard-B receptacle
- USB 3 Standard-A plug
- USB 3 Micro-B plug
- USB 2 Standard-B plug

It has been replaced by the USB-C plug.

### Naming and Standards
The official name for this entity is the USB 3.1 Standard-B plug. This designation is referenced in documents from the USB Implementers Forum, dated 2025-04-19.
It is also known by several aliases, including:
- USB 10Gbps Standard-B plug
- SuperSpeed+ USB Standard-B plug
- SS+ USB Standard-B plug
- USB 3.0 Standard-B plug
- USB SuperSpeed Standard-B plug
- SuperSpeed USB Standard-B plug
- USB 5Gbps Standard-B plug

The standards body responsible for its specifications is the USB Implementers Forum.

### Physical Characteristics
The USB 3 Standard-B plug is comprised of various parts, including leads.
A visual representation of the plug is available as an image: `https://commons.wikimedia.org/wiki/Special:FilePath/USB_connector_illustration,_to_scale,_front_view,_legacy,_USB_3_Standard-B_plug.svg`.
A schematic illustrating its pinout is also available: `https://commons.wikimedia.org/wiki/Special:FilePath/USB_connector_illustration,_to_scale,_front_view,_legacy,_USB_3_Standard-B_plug,_with_pinout.svg`.

### Pinout
The USB 3 Standard-B plug features a 9-pin configuration, with each pin serving a specific function:
- **Pin 1:** VBUS
    - Color: red
    - Voltage: 5V
    - Type: IC power-supply pin
- **Pin 2:** D−
    - Color: white
- **Pin 3:** D+
    - Color: green
- **Pin 4:** GND
    - Color: black
    - Type: ground
- **Pin 5:** SSTX−
- **Pin 6:** SSTX+
- **Pin 7:** GND_DRAIN
- **Pin 8:** SSRX−
- **Pin 9:** SSRX+

These pin details are referenced in USB 3.1 legacy cable and connector revisions, USB 2.0 specifications, and USB 3.1 legacy connectors and cable assemblies compliance documents from the USB.org document library.

## References

1. [Source](https://www.usb.org/document-library/usb-31-legacy-cable-and-connector-revision-10)
2. [Source](https://www.usb.org/document-library/usb-type-cr-cable-and-connector-specification-release-24)
3. [Source](https://www.usb.org/document-library/usb-32-revision-11-june-2022)
4. [Source](https://www.usb.org/document-library/usb-type-cr-connectors-and-cable-assemblies-compliance-document-rev-21b)
5. [Source](https://www.usb.org/document-library/universal-serial-bus-31-legacy-connectors-and-cable-assemblies-compliance-document)
6. [Source](https://www.usb.org/document-library/usb-20-specification)