# USB 2 Type-AB receptacle

> the class of USB 2 receptacles (those which carry only USB 1–2 and power) which accept both Type‑A and Type‑B plugs and preceded the USB 2 Type‑C receptacle, which replaces them

**Wikidata**: [Q133873706](https://www.wikidata.org/wiki/Q133873706)  
**Source**: https://4ort.xyz/entity/usb-2-type-ab-receptacle

## Summary
The USB 2 Type-AB receptacle is a legacy USB connector that supports USB 1 and 2 protocols plus power delivery, and accepts both Type-A and Type-B plugs. It was widely used in early USB devices before being succeeded by the USB 2 Type-C receptacle.

## Key Facts
- Official name: USB 2 Type-AB receptacle  
- Function: Supports USB 1–2 data transfer and power delivery  
- Plug compatibility: Accepts both USB Type-A and Type-B plugs  
- Replaced by: USB 2 Type-C receptacle  
- Classification: Subclass of USB 2 legacy receptacle, USB Type-AB receptacle, and USB 2 legacy connector  
- Aliases: USB 2.0 Type-AB connector, USB 2 On-The-Go receptacle, USB 1.1 Type-AB receptacle  
- Different from: USB 2 Type-A, USB 2 Type-B, USB 2 Type-C, USB 3 Micro-AB receptacles  
- Image reference: [Wikimedia illustration](https://commons.wikimedia.org/wiki/Special:FilePath/USB_connector_illustration,_to_scale,_grouping,_legacy,_USB_2_Type-AB_(receptacles).svg)  
- Standards documentation: Referenced in USB 3.1 and USB 3.2 legacy compliance documents  

## FAQs
### Q: What devices use USB 2 Type-AB receptacles?
A: These were commonly found on older peripherals such as early smartphones, tablets, and some digital cameras supporting USB On-The-Go functionality.

### Q: Can I plug a USB-C cable into a USB 2 Type-AB port?
A: No. USB 2 Type-AB ports are physically incompatible with USB-C plugs. An adapter or different cable is required.

### Q: Is USB 2 Type-AB still in use today?
A: It has been largely phased out in favor of USB Type-C but may still appear in legacy hardware or specialized equipment.

## Why It Matters
The USB 2 Type-AB receptacle played a critical role during the transition from fixed-role USB systems to more flexible, host/device-switchable connections enabled by USB On-The-Go (OTG). As one of the earliest standardized dual-plug-compatible interfaces, it allowed portable devices like early smartphones and tablets to act either as hosts or peripherals depending on the connected device. Though now obsolete, its design informed later standards including USB Type-C, making it historically significant in the evolution of universal connectivity solutions.

## Notable For
- First mainstream receptacle supporting both Type-A and Type-B plug insertion  
- Enabled early adoption of USB On-The-Go (OTG) technology in mobile devices  
- Standardized solution bridging desktop and portable electronics before USB-C  
- Physically distinct from single-type receptacles like USB A/B  
- Fully superseded by USB 2 Type-C in modern applications  

## Body

### Definition and Role
The USB 2 Type-AB receptacle is a class of legacy USB 2 connector designed to accept both standard USB Type-A and Type-B plugs. This dual-compatibility made it ideal for implementing USB On-The-Go (OTG), allowing small devices to switch roles between host and peripheral dynamically.

### Technical Specifications
- **Protocols Supported**: USB 1.0, USB 1.1, USB 2.0  
- **Power Delivery**: Yes, up to 5V as per USB 2.0 specification  
- **Data Transfer Rates**: Up to 480 Mbps (Hi-Speed USB)  
- **Plug Types Accepted**: Standard USB Type-A and Type-B plugs only  
- **Connector Class**: Legacy; categorized under USB 2 legacy receptacles  

### Historical Context
Before the introduction of USB Type-C, the need arose for a unified interface capable of handling multiple plug types within constrained form factors—especially in emerging portable electronics. The Type-AB receptacle filled this gap by combining physical versatility with backward compatibility across existing USB generations.

It preceded the development of smaller variants like the USB Mini-AB and USB Micro-AB, which further refined OTG capabilities in increasingly compact devices.

### Relationship to Other Connectors
- **Predecessor lineage**:
  - Superseded earlier non-reversible solutions
  - Evolved into compact formats like USB Mini-AB and USB Micro-AB
- **Successor**:
  - Entirely replaced by USB 2 Type-C receptacle in new designs
- **Differentiation**:
  - Unlike dedicated Type-A or Type-B ports, AB versions allow reversible-like flexibility without true reversibility

### Documentation and Compliance
Defined in official USB Implementers Forum documents including:
- *Universal Serial Bus 3.1 Legacy Connectors and Cable Assemblies Compliance Document* (Revision 1.0)
- *USB 3.2 Specification Revision 1.1*

These documents classify and regulate how manufacturers implement and label these legacy connectors to ensure interoperability and prevent confusion with newer standards.

## 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)