# USB 2 Micro-B receptacle > the most compact legacy USB 2 receptacle used in peripheral devices, replaced by the USB 2 Type‑C receptacle **Wikidata**: [Q102144751](https://www.wikidata.org/wiki/Q102144751) **Source**: https://4ort.xyz/entity/usb-2-micro-b-receptacle ## Summary The USB 2 Micro-B receptacle is the most compact legacy USB 2 receptacle designed for peripheral devices. It exclusively carries USB 1–2 signals and power and has been superseded by the USB 2 Type-C receptacle. ## Key Facts - **Official Name**: USB 2.0 Micro-B receptacle (per USB.org specifications, last updated 2025-05-10). - **Function**: Designed for peripheral device endpoints, supporting only USB 1–2 data transfer and power delivery. - **Replacement Status**: It replaced the USB Mini-B receptacle and was later replaced by the USB 2 Type-C receptacle. - **Pin Configuration**: 5-pin layout: VBUS (5V power, red), D− (data negative, white), D+ (data positive, green), ID (USB On-The-Go, pin 4), and GND (ground, black). - **Physical Design**: The most compact legacy USB 2 receptacle for peripherals, featuring a trapezical shape with a mandatory black insulator. - **Connectivity**: Pairs exclusively with the USB 2 Micro-B plug. - **Legacy Classification**: Belongs to classes of USB Micro-B receptacles, USB 2 Micro-B connectors, and USB 2 Type-B receptacles. ## FAQs ### Q: What devices used the USB 2 Micro-B receptacle? A: It was commonly used in older peripheral devices like smartphones, external hard drives, MP3 players, and portable chargers due to its compact size and USB 1–2 support. ### Q: How does the USB 2 Micro-B receptacle differ from USB 3 Micro-B? A: USB 2 Micro-B carries only USB 1–2 signals and has 5 pins, while USB 3 Micro-B adds extra pins for SuperSpeed data, making them physically incompatible. ### Q: Why was the USB 2 Micro-B receptacle replaced? A: Its successor, USB 2 Type-C (USB-C), offers reversibility, higher power delivery, and USB 3+ support, addressing USB 2 Micro-B’s limitations in speed, durability, and user-friendliness. ### Q: What is the ID pin used for? A: The ID pin (pin 4) enables USB On-The-Go functionality, allowing devices to switch between host and peripheral roles (e.g., connecting a phone directly to a flash drive). ## Why It Matters The USB 2 Micro-B receptacle standardized compact connectivity for mobile and portable devices, eliminating bulkier Mini-B connectors. Its widespread adoption enabled thinner device designs and reliable USB 1–2 performance, setting precedents for future USB standards. Though phased out by USB-C, it remains a critical legacy interface in existing devices, ensuring interoperability and extending product lifecycles. It bridged the gap between early USB peripherals and modern reversible charging, influencing decades of consumer electronics design. ## Notable For - **Compactness**: The smallest legacy USB 2 receptacle for peripherals, crucial for mobile and portable devices. - **Universal Adoption**: Dominated peripheral connectivity from the late 2000s to mid-2010s across phones, storage drives, and accessories. - **USB On-The-Go Integration**: First widely adopted USB receptacle with an ID pin for dual host/peripheral roles. - **Mandatory Black Insulator**: Required in specifications to distinguish it from non-standard alternatives. - **Legacy Longevity**: Despite obsolescence, it remains operational in billions of devices due to backward compatibility. ## Body ### Overview The USB 2 Micro-B receptacle is a legacy USB Type-B interface for peripheral devices, supporting USB 1–2 speeds and power. It is the most compact of its class and was finalized before USB-C. ### Technical Specifications - **Pinout**: - Pin 1: VBUS (5V power, red, IC power-supply pin). - Pin 2: D− (data negative, white). - Pin 3: D+ (data positive, green). - Pin 4: ID (USB On-The-Go). - Pin 5: GND (ground, black). - **Leads**: Contains 10 lead components (per structured properties). - **Dimensions**: Defined as the most compact legacy USB 2 receptacle; exact dimensions unspecified in source. - **Color**: Requires a black insulator for compliance. ### Classification and Relationships - **Instance Of**: USB Micro-B receptacle (class), USB 2 Micro-B connector (class), USB 2 Micro receptacle (class), USB 2 Type-B receptacle (class). - **Replaces**: USB Mini-B receptacle. - **Replaced By**: USB-C receptacle. - **Opposite Of**: USB 2 Micro-B plug. - **Connects With**: USB 2 Micro-B plug. - **Different From**: USB 2 Micro-B plug, USB 2 Micro-AB receptacle, USB 3 Micro-B receptacle, and others. ### Legacy and Context - **Legacy Status**: A pre-C (pre-Type-C) USB peripheral endpoint, superseded due to USB-C’s reversibility and higher bandwidth. - **Ubiquity**: Historically widespread in mobile devices and storage; now primarily in legacy hardware. - **Revisions**: Officially defined in USB 2.0 specifications, with references to USB.org documents (2025-05-10). ### Common Aliases - USB 2.0 Micro-B port, Micro-USB 2.0 port, USB Hi-Speed Micro-B receptacle. - USB 1.1/1.0 Micro-B receptacle (backward-compatible variants). - Micro-USB 2.0 Type-B receptacle, Micro-USB 2 Type-B receptacle. ### Media Resources - **Image**: [SVG illustration with pinout](https://commons.wikimedia.org/wiki/Special:FilePath/USB_connector_illustration,_to_scale,_front_view,_legacy,_USB_2_Micro-B_receptacle.svg). - **Schematic**: [Pinout diagram](https://commons.wikimedia.org/wiki/Special:FilePath/USB_connector_illustration,_to_scale,_front_view,_legacy,_USB_2_Micro-B_receptacle,_with_pinout.svg). - **3D Model**: [STL file](https://commons.wikimedia.org/wiki/Special:FilePath/USB_Micro-B_Molex_47346-0001.stl). ## 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)