# USB Standard receptacle > a class of legacy USB receptacles that preceded USB-C, along with Micro and Mini **Wikidata**: [Q133871737](https://www.wikidata.org/wiki/Q133871737) **Source**: https://4ort.xyz/entity/usb-standard-receptacle ## Summary A USB Standard receptacle is a class of legacy USB ports that preceded the introduction of USB-C. It encompasses the larger, non-reversible connectors—specifically the Standard-A and Standard-B types—used in early USB generations (such as USB 2.0 and USB 3.0), serving as the fixed interface on host devices and peripherals rather than the plug end of a cable. ## Key Facts * **Classification:** The USB Standard receptacle is a subclass of the "USB Standard connector" and the broader category of "legacy USB receptacle." * **Predecessor Status:** It is defined as a legacy class that preceded USB-C, existing alongside (but distinct from) Micro and Mini USB receptacles. * **Component Types:** This class includes the **USB Standard-A receptacle** (typically the host end) and the **USB Standard-B receptacle** (typically the peripheral device end). * **Generations:** It encompasses specific sub-classes such as the **USB 2 Standard receptacle** and the **USB 3 Standard receptacle**. * **Distinctions:** It is structurally different from the "USB Standard plug" (the movable cable end) and is distinct from modern or smaller form factors like USB-C, USB Micro, and USB Mini. * **Visual Representation:** Common visual examples include the USB 3 Standard-A, USB 2 Standard-A, USB 3 Standard-B, USB Powered-B, and USB 2 Standard-B receptacles. * **Alias:** It is also known as the "Standard USB receptacle." ## FAQs ### Q: How does a USB Standard receptacle differ from a USB Standard plug? A: The receptacle is the fixed connector port attached to a device (such as a computer or printer), whereas the plug is the movable connector attached to the end of a cable. ### Q: Is USB Standard receptacle the same as USB-C? A: No. The USB Standard receptacle is a legacy class of connectors that *preceded* USB-C. USB-C was designed to replace this standard class along with the Micro and Mini variants. ### Q: What are the main types of USB Standard receptacles? A: The main types include the Standard-A (usually found on computers/host controllers) and Standard-B (usually found on peripheral devices like printers), which come in USB 2.0 and USB 3.0 variations. ## Why It Matters The USB Standard receptacle represents the foundational physical interface that defined the Universal Serial Bus standard for nearly two decades. Before the advent of the reversible, universal USB-C connector, the Standard receptacle was the primary method for connecting peripherals to host computers, characterized by its distinct, non-reversible rectangular (Type-A) and square (Type-B) shapes. Understanding this classification is essential for maintaining and supporting legacy hardware, as millions of devices still rely on these ports. The distinction matters because it highlights the evolution of connectivity technology: the industry moved from these specific, direction-dependent "Standard" shapes to the more versatile USB-C. This entity groups the various "classic" USB ports (USB 2.0 and 3.0, Type A and B) into a single category to differentiate them from the smaller mobile-focused "Mini/Micro" era and the current "USB-C" era. ## Notable For * **Ubiquity:** Being the most recognizable "classic" USB port shape found on computers and peripherals prior to USB-C. * **Hierarchy:** Serving as the parent class for the widely used USB Standard-A and USB Standard-B connectors. * **Longevity:** Spanning multiple USB generations, including the distinct internal architectures of USB 2.0 and USB 3.0. * **Distinction:** Being explicitly differentiated from the "plug" (the cable end) and the "Mini/Micro" (mobile) form factors. ## Body ### Definition and Taxonomy The **USB Standard receptacle** is a specific class of connector defined within the USB specification hierarchy. It is structurally classified as a **subclass** of the "USB Standard connector" and the "legacy USB receptacle." The term serves as a catch-all for the fixed, device-side ports used in the pre-USB-C era, distinguishing them from the cable-side "plugs" and the smaller "Mini" and "Micro" form factors designed for portable devices. ### Variants and Sub-Classes The class comprises several distinct receptacle types based on generation and intended use: * **USB Standard-A receptacle:** The "host" end connector, recognizable by its rectangular shape. * **USB Standard-B receptacle:** The "peripheral" end connector, typically square-shaped, used for devices like printers. * **USB 2 Standard receptacle:** The earlier iteration supporting USB 2.0 speeds. * **USB 3 Standard receptacle:** The later iteration (often colored blue) supporting higher USB 3.0 data transfer rates. * **USB Powered-B receptacle:** A specialized variant seen in USB 3.0 specifications. ### Historical Context and Succession According to USB documentation (including USB 3.1 Legacy Cable and Connector revisions), this class is explicitly categorized as "legacy." It is defined as the family of connectors that **preceded USB-C**. While USB-C is now the modern standard intended to replace all prior connectors, the USB Standard receptacle remains a critical point of reference for identifying legacy hardware compatibility. ### Identification Visually, these receptacles are characterized by their non-reversible design (plugs must be inserted right-side up). They are physically larger than the Mini and Micro variants. The official documentation refers to this class simply as "USB Standard plug" (in reference to the mating interface mechanics), but in functional classification, the *receptacle* is the port receiving the plug. ## 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)