# USB 3 Micro receptacle > the latter class of legacy Micro receptacles that preceded USB-C **Wikidata**: [Q133873514](https://www.wikidata.org/wiki/Q133873514) **Source**: https://4ort.xyz/entity/usb-3-micro-receptacle ## Summary The USB 3 Micro receptacle is a class of legacy USB ports that served as the succeeding standard for mobile and peripheral connections prior to the introduction of USB-C. Officially designated as the USB 3.1 Micro receptacle, it is physically distinct from earlier USB 2.0 Micro ports and modern USB-C ports. It has been effectively replaced in modern devices by the USB-C receptacle. ## Key Facts * **Official Name:** USB 3.1 Micro receptacle. * **Class Hierarchy:** A subclass of the USB 3 Micro connector, the USB 3 receptacle, and the broader USB Micro receptacle class. * **Successor:** Replaced by the USB-C receptacle. * **Primary Variants:** Includes the **USB 3 Micro-AB receptacle** (which accepts both Micro-A and Micro-B plugs) and the **USB 3 Micro-B receptacle** (typically found on peripheral devices). * **Legacy Status:** Defined as the "latter class" of legacy Micro connectors that preceded the USB-C standard. * **Common Aliases:** Known variously as USB 3.0 Micro receptacle, SuperSpeed Micro USB receptacle, and Micro-USB 3.1 receptacle. * **Distinctions:** Specifically differentiated from the USB 3 Micro *plug*, the USB 2 Micro receptacle, and the USB 3 Standard receptacle. ## FAQs ### Q: Is the USB 3 Micro receptacle the same as the USB-C port? A: No. The USB 3 Micro receptacle is a legacy port that physically preceded the USB-C receptacle. While USB-C has replaced it in modern devices, they are distinct form factors with different shapes and pin configurations. ### Q: What is the difference between USB 3 Micro-AB and USB 3 Micro-B receptacles? A: The **USB 3 Micro-B receptacle** is designed specifically for peripheral devices (the "B" end), whereas the **USB 3 Micro-AB receptacle** is a legacy port capable of accepting both Micro-A and Micro-B plugs. ### Q: Can I plug a standard USB 2.0 Micro cable into a USB 3 Micro receptacle? A: While source material defines them as distinct classes ("different from USB 2 Micro receptacle"), the USB 3 Micro-B design was mechanically backward-compatible in specific contexts. However, physically, the USB 3 Micro receptacle has additional pins and a different shape compared to the USB 2 Micro receptacle. ## Why It Matters The USB 3 Micro receptacle represents a critical transitional phase in the evolution of universal serial bus technology. As the "latter class of legacy Micro receptacles," it bridged the gap between the slower USB 2.0 era and the modern, reversible USB-C standard. Its development was driven by the need for "SuperSpeed" data transfer rates in increasingly compact devices, a capability that the previous generation of Micro connectors could not support efficiently. This component matters significantly to hardware historians, legacy tech maintainers, and industrial designers because it illustrates the rapid iteration of connectivity standards. It introduced the complexities of the USB 3.0/3.1 protocol to the micro form factor but was ultimately short-lived, being fully superseded by the more versatile Full-Featured Type-C receptacle. Understanding this receptacle is essential for correctly identifying cables and ports for older high-speed external hard drives and legacy mobile devices that predate the universal adoption of USB-C. ## Notable For * **Predecessor to USB-C:** Being the immediate legacy class of receptacles that existed before the industry-wide shift to USB-C. * **SuperSpeed Integration:** Bringing USB 3.0/3.1 data capabilities to the Micro form factor (evidenced by the alias "SuperSpeed Micro USB receptacle"). * **Micro-AB Versatility:** Including a variant (Micro-AB) capable of accepting multiple plug formats, a feature later standardized and expanded upon in USB-C. * **Official Nomenclature:** Being officially classified under the "USB 3.1" naming convention, despite often being referred to colloquially as "USB 3.0." ## Body ### Classification and Hierarchy The USB 3 Micro receptacle is a specific class of connector interface defined within the USB 3.1 legacy specifications. It sits within a hierarchy as a subclass of the **USB 3 Micro connector**, the **USB 3 receptacle**, and the general **USB Micro receptacle**. It is categorized as a "legacy" connector, distinct from the modern USB-C standard. ### Variants There are two primary implementations of the USB 3 Micro receptacle identified in the knowledge base: * **USB 3 Micro-AB Receptacle:** A versatile legacy port that accepted all Micro-A and Micro-B plugs. This functionality has been replaced in modern standards by the Full-Featured Type-C receptacle. * **USB 3 Micro-B Receptacle:** The standard peripheral-side connector, identifiable by its specific shape indicating the "B" (device) end of the connection. ### Evolution and Replacement This class of receptacle is defined by its temporal position in technology history. It is described as the class that "preceded USB-C." Consequently, it has been formally **replaced by the USB-C receptacle**. The USB-C standard effectively consolidated the functions and form factors of the USB 3 Micro variants (including the AB and B types) into a single, reversible connector. ### Nomenclature The official name for this entity is the **USB 3.1 Micro receptacle**. However, due to revisions in USB marketing and specifications over time, it is also known by several aliases, including: * USB 3.0 Micro receptacle * Micro-USB 3.1 receptacle * USB SuperSpeed Micro receptacle ## 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/universal-serial-bus-31-legacy-connectors-and-cable-assemblies-compliance-document) 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/usb-type-cr-cable-and-connector-specification-release-24)