# USB 2 Micro-AB receptacle > the legacy USB 2 receptacle which accepts both USB 2 Micro‑A and USB 2 Micro‑B plugs, replaced by the USB 2 Type‑C receptacle **Wikidata**: [Q102144729](https://www.wikidata.org/wiki/Q102144729) **Source**: https://4ort.xyz/entity/usb-2-micro-ab-receptacle ## Summary The USB 2 Micro-AB receptacle is a legacy USB connector designed to accept both USB 2 Micro-A and USB 2 Micro-B plugs. It served as a dual-purpose port carrying USB 1–2 data and power but has been effectively replaced by the USB 2 Type-C receptacle in modern devices. ## Key Facts * **Official Name:** USB 2.0 Micro-AB receptacle. * **Function:** Accepts both USB 2 Micro-A and USB 2 Micro-B plugs. * **Successor:** Replaced by the USB-C receptacle. * **Predecessors:** Replaced the USB Mini-A receptacle and the USB Mini-AB receptacle. * **Pin Configuration:** Features 5 pins (VBUS, D−, D+, ID, GND). * **Physical Composition:** Contains 10 leads. * **Insulator Color:** Features a grey insulator color as per specification. * **Classification:** It is an instance of a USB 2 Type-AB receptacle and a USB Micro-AB receptacle. * **Supported Standards:** Carries USB 1–2 data and power; the ID pin supports USB On-The-Go (OTG). ## FAQs ### Q: What is the difference between a USB 2 Micro-AB receptacle and a Micro-B receptacle? A: A USB 2 Micro-B receptacle typically only accepts a Micro-B plug, whereas the Micro-AB receptacle is designed to accept both USB 2 Micro-A and USB 2 Micro-B plugs. ### Q: Is the USB 2 Micro-AB receptacle still used in new devices? A: It is considered a legacy connector. It belongs to the class of USB connectors that preceded USB Type-C, which has since replaced this receptacle in modern hardware implementations. ### Q: What is the purpose of the ID pin in this receptacle? A: The ID pin (Pin 4) is included to support USB On-The-Go (OTG) functionality, allowing devices to act as either hosts or peripherals. ### Q: Does this receptacle support USB 3.0 speeds? A: No, the entity is strictly defined as a USB 2 receptacle carrying USB 1–2 signals. It is distinct from the USB 3 Micro-AB receptacle. ## Why It Matters The USB 2 Micro-AB receptacle represents a transitional phase in the evolution of universal serial bus technology, specifically addressing the need for compact, reversible connectivity in mobile devices before the advent of USB-C. By defining a receptacle that could accept both Micro-A and Micro-B plugs, the specification allowed device manufacturers greater flexibility in designing On-The-Go (OTG) host and peripheral roles without requiring distinct port types for different cable orientations. Although it is now categorized as a legacy connector replaced entirely by the USB 2 Type-C receptacle, the Micro-AB standard was crucial for dual-role devices (like smartphones and tablets) in the pre-Type-C era. It consolidated the functionality of preceding Mini connectors (Mini-A and Mini-AB) into a smaller form factor, paving the way for the slimmer electronics of its time while maintaining the power and data capabilities of the USB 2.0 standard. ## Notable For * **Universal Micro Compatibility:** Being the specific USB 2 class of receptacle capable of accepting both Type-A and Type-B Micro plugs. * **Pre-Type-C Reversibility:** Offering a solution for dual-plug types prior to the introduction of the fully reversible USB Type-C. * **Distinct Insulator:** Being distinctively identified by a required grey insulator color in its visual specification. * **Legacy Status:** Being explicitly defined as a legacy connector class that has been fully superseded by USB Type-C. ## Body ### Technical Specifications The USB 2 Micro-AB receptacle is a 5-pin connector. Its pinout is defined as follows: * **Pin 1 (VBUS):** Red, IC power-supply pin (5 V). * **Pin 2 (D−):** White, Data minus. * **Pin 3 (D+):** Green, Data plus. * **Pin 4 (ID):** Used for USB On-The-Go (OTG) identification. * **Pin 5 (GND):** Black, Ground. The connector assembly includes 10 leads. Visually, the standard mandates a grey insulator color to distinguish it from other USB receptacle types. ### Classification and Hierarchy The USB 2 Micro-AB receptacle is an instance of multiple connector classes. It falls under the "USB 2 legacy connector" and "USB 2 Micro connector" classes, indicating it carries only USB 1–2 data and power. Specifically, it is an instance of the "USB Micro-AB receptacle" class (receptacles that accept both A and B types) and the "USB 2 Type-AB receptacle" class. ### Evolution and Replacement This receptacle was introduced to replace the bulkier USB Mini-A and USB Mini-AB receptacles. However, with the development of the USB Type-C standard, the USB 2 Micro-AB receptacle has itself been replaced. The USB 2 Type-C receptacle is the modern successor, superseding all legacy USB 2 connectors including the Micro-AB. ### Official Nomenclature While commonly referred to as the USB 2 Micro-AB receptacle, official documentation lists several aliases including USB Hi-Speed Micro-AB receptacle, USB 1.1 Micro-AB receptacle, USB 1 Micro-AB receptacle, and Micro-USB 2.0 Type-AB receptacle. It is distinct from the USB 3 Micro-AB receptacle, which supports higher data transfer speeds. ## 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)