# legacy USB receptacle > the class of all USB receptacles other than Type‑C (USB‑C), which replaces all of them **Wikidata**: [Q12397946](https://www.wikidata.org/wiki/Q12397946) **Source**: https://4ort.xyz/entity/legacy-usb-receptacle ## Summary A legacy USB receptacle is the class of all USB ports and sockets other than Type-C (USB-C). These receptacles, which include various forms such as Standard-A, Standard-B, Micro, and Mini, are the predecessors to the modern USB-C standard. The category encompasses all older USB female connectors that have been functionally replaced by USB-C technology. ## Key Facts * **Definition:** The class of USB receptacles defined as being "other than Type-C (USB-C)." * **Successor:** All legacy USB receptacles have been replaced by the USB-C receptacle. * **Parent Classes:** Belongs to the class of "USB receptacle" and "legacy USB connector." * **Major Sub-classes:** Includes USB Standard, Mini, Micro, Type-A, Type-B, and Type-AB receptacles. * **Compatibility:** Designed to accept legacy USB plugs. * **Distinction:** Distinct from the USB-C receptacle and the legacy USB plug (the male counterpart). * **Common Aliases:** Also known as USB legacy receptacle, legacy USB port, legacy USB socket, or USB legacy socket. * **Official References:** Defined in USB-IF documentation including the "USB 3.1 Legacy Cable and Connector" and "USB Type-C Cable and Connector Specification." ## FAQs ### Q: What is the difference between a legacy USB receptacle and a USB-C receptacle? A: A legacy USB receptacle refers to any USB port that is not Type-C, such as the rectangular Standard-A or the square Standard-B ports. The USB-C receptacle is the modern standard designed to replace all of these legacy formats. ### Q: What types of connectors fall under the legacy USB receptacle class? A: This class includes Standard (A and B), Mini (Mini-A, Mini-B, Mini-AB), and Micro (Micro-A, Micro-B, Micro-AB) receptacles. It also covers specific generations like USB 2 legacy and USB 3 receptacles. ### Q: Are legacy USB receptacles still used in new devices? A: While defined as "legacy" because they are replaced by USB-C, these receptacles (particularly Standard-A) remain common in many existing hardware setups. However, the industry standard has shifted toward USB-C for new implementations. ## Why It Matters The concept of the legacy USB receptacle is significant because it serves as a collective term for the diverse ecosystem of USB hardware that preceded the current universal standard. For decades, users and manufacturers navigated a fragmented landscape of different shapes (Standard, Mini, Micro) and pin configurations (USB 2 vs. USB 3). Grouping these under "legacy USB receptacle" acknowledges the technological shift toward the USB-C era, which aims to unify connectivity. Understanding this classification is crucial for hardware documentation, backward compatibility support, and regulatory compliance (such as the movement toward common chargers). It helps delineate the boundary between older, often non-reversible, and function-specific ports and the modern, multi-functional USB-C interface. ## Notable For * **Comprehensive Scope:** Encompasses the entire history of USB physical connectors prior to the Type-C revolution. * **Obsolescence:** It is the only major class of connectors explicitly defined by the existence of a successor (USB-C) intended to replace it entirely. * **Variety of Form Factors:** Includes the once-ubiquitous Standard-A (host), the peripheral-focused Standard-B, and the mobile-focused Mini and Micro formats. * **Evolutionary Marker:** Marks the transition from specific-purpose ports (e.g., Mini-AB for On-The-Go) to a universal solution. ## Body ### Definition and Classification The term **legacy USB receptacle** refers to the superclass of all USB female connectors that are not of the Type-C design. In technical taxonomies, it is a subclass of both "USB receptacle" and "legacy USB connector." This category exists to classify the hardware that fulfilled USB connectivity needs from the inception of the standard until the introduction of USB-C. ### Major Sub-Classes The legacy USB receptacle class is composed of several distinct families of connectors, each with specific use cases: * **Standard Receptacles:** These include the iconic rectangular **USB Type-A receptacle** (typically found on hosts and computers) and the squarish **USB Type-B receptacle** (typically found on printers and peripherals). * **Mini Receptacles:** Predominantly used in early mobile devices. This includes the **USB Mini-B receptacle** and the deprecated **USB Mini-A** and **Mini-AB** receptacles. * **Micro Receptacles:** The standard for smartphones before USB-C. This includes the **USB Micro-B receptacle** and the **USB Micro-AB receptacle**. * **Type-AB Receptacles:** A specialized class of legacy receptacles capable of accepting both Type-A and Type-B plugs. ### Technical Evolution These receptacles evolved through USB speed generations. The **USB 2 legacy receptacle** carries only USB 1–2 signals and power, while the **USB 3 receptacle** added the necessary pins for higher data transfer rates (SuperSpeed). Despite these internal upgrades, the physical forms remained distinct from the modern USB-C standard. ### Replacement by USB-C The defining characteristic of the legacy USB receptacle is its status as a deprecated technology in the face of the **USB-C receptacle**. The USB-C standard was developed to consolidate the confusion of cable types (A-to-B, A-to-Micro-B, etc.) into a single, reversible, and universal connector. Consequently, the legacy USB receptacle is classified as the technology that "preceded USB-C, which replaces all of them." ## 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)