# USB Micro-AB receptacle

> a class of legacy USB receptacles that preceded USB-C, “AB” indicating they accept both Type-A and Type-B plugs

**Wikidata**: [Q133873467](https://www.wikidata.org/wiki/Q133873467)  
**Source**: https://4ort.xyz/entity/usb-micro-ab-receptacle

## Summary
The USB Micro-AB receptacle is a legacy USB connector that accepts both Micro-A and Micro-B plugs, serving as a reversible alternative before the introduction of USB-C. It was used primarily in USB 2.0 and USB 3.x implementations for devices requiring dual plug compatibility. This receptacle has since been superseded by more modern and versatile connectors like USB Type-C.

## Key Facts
- Official name: USB Micro-AB receptacle  
- Aliases: USB Micro-AB connector, Micro-USB Type-AB receptacle, Micro-USB Type-AB connector  
- Subclass of: USB Micro receptacle, USB Type-AB receptacle, Micro-USB  
- Accepts: USB 2.0 Micro-A and Micro-B plugs; USB 3.x Micro-A and Micro-B plugs  
- Replaced by: USB Type-C receptacles (e.g., USB 2 Type-C, Full-Featured Type-C)  
- Different from: USB Mini-AB receptacle  
- Defined in official standards including USB 3.1 Legacy Cable and Connector Revision 1.0 and USB 3.2 Revision 1.1  
- Image reference: [Wikimedia Commons](https://commons.wikimedia.org/wiki/Special:FilePath/USB_connector_illustration,_to_scale,_grouping,_legacy,_Micro-AB_(receptacles).svg)  
- Sitelink count: 1  

## FAQs
### Q: What is a USB Micro-AB receptacle used for?
A: The USB Micro-AB receptacle allows a device to accept both USB Micro-A and Micro-B plugs, offering flexibility in connectivity for peripherals such as mobile devices and external drives. It was commonly used in legacy USB 2.0 and USB 3.x systems.

### Q: Is USB Micro-AB still in use today?
A: No, USB Micro-AB is considered a legacy connector and has largely been replaced by USB Type-C, which offers better versatility, higher performance, and a reversible design.

### Q: How does USB Micro-AB differ from USB Mini-AB?
A: USB Micro-AB is part of the Micro-USB family and supports both Micro-A and Micro-B plugs, while USB Mini-AB belongs to the older Mini-USB family and supports Mini-A and Mini-B plugs. They are physically and electrically incompatible.

## Why It Matters
The USB Micro-AB receptacle played a transitional role in the evolution of USB technology by enabling greater flexibility in plug compatibility during the shift from earlier USB form factors. Before the widespread adoption of USB Type-C, it allowed manufacturers and users to support multiple plug types within a single port, reducing the need for separate connectors. While now obsolete, it represents an important step toward universal interoperability in USB design and influenced later developments in reversible connector architecture.

## Notable For
- Being one of the few USB receptacles designed to accept two distinct plug types (Micro-A and Micro-B)  
- Serving as a bridge between legacy USB designs and modern reversible connectors like USB-C  
- Supporting both USB 2.0 and USB 3.x plug standards depending on implementation  
- Being officially defined in multiple USB-IF compliance documents, including USB 3.1 and USB 3.2 legacy specifications  
- Representing a niche but critical solution in early mobile and peripheral device design  

## Body

### Overview
The USB Micro-AB receptacle is a type of legacy USB connector designed to accept both USB Micro-A and USB Micro-B plugs. It was introduced as part of the broader Micro-USB standard and served as a flexible interface in devices needing compatibility with multiple plug types without requiring separate ports.

### Technical Specifications
- **Plug Compatibility**:
  - Accepts USB 2.0 Micro-A and Micro-B plugs (in USB 2 implementations)
  - Accepts USB 3.x Micro-A and Micro-B plugs (in USB 3 implementations)
- **Receptacle Types**:
  - USB 2 Micro-AB receptacle
  - USB 3 Micro-AB receptacle
- **Standards Documentation**:
  - Defined in *USB 3.1 Legacy Cable and Connector Revision 1.0*
  - Referenced in *Universal Serial Bus 3.1 Legacy Connectors and Cable Assemblies Compliance Document*
  - Updated under *USB 3.2 Revision 1.1*

### Relationship to Other USB Connectors
- **Parent Classes**:
  - USB Micro receptacle
  - USB Type-AB receptacle
  - Micro-USB
- **Different From**:
  - USB Mini-AB receptacle (older, non-interchangeable form factor)
- **Successor**:
  - Replaced by USB Type-C receptacles, including USB 2 Type-C and Full-Featured Type-C

### Obsolescence and Replacement
With the rise of USB Type-C—which provides a universally reversible, high-performance interface—the USB Micro-AB receptacle has become obsolete. Modern USB specifications no longer recommend its use, focusing instead on promoting Type-C as the primary connector for future-proof designs.

### Visual Representation
An illustration showing both USB 2 and USB 3 Micro-AB receptacles is available via Wikimedia Commons, labeled as ["USB_connector_illustration,_to_scale,_grouping,_legacy,_Micro-AB_(receptacles).svg"](https://commons.wikimedia.org/wiki/Special:FilePath/USB_connector_illustration,_to_scale,_grouping,_legacy,_Micro-AB_(receptacles).svg), depicting their physical characteristics and relative scale.

## 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)