# USB 2 Standard receptacle

> the earlier class of legacy (pre-C) USB Standard receptacles

**Wikidata**: [Q133869918](https://www.wikidata.org/wiki/Q133869918)  
**Source**: https://4ort.xyz/entity/usb-2-standard-receptacle

## Summary
The USB 2 Standard receptacle is a legacy USB connector class that preceded USB-C, supporting USB 1–2 data transfer and power delivery. It includes the Standard-A (host) and Standard-B (peripheral) designs, now replaced by the USB Type-C receptacle. These connectors were widely used before the introduction of USB-C.

## Key Facts
- **Official Name**: USB 2 Standard receptacle, as defined in USB-IF specifications.
- **Replaced By**: USB 2 Type-C receptacle, which consolidates all legacy connector types.
- **Subclasses**: Includes USB 2 Standard-A (host) and Standard-B (peripheral) receptacles.
- **Aliases**: Known as USB 1.0/1.1/2.0 Standard receptacle, reflecting backward compatibility.
- **Standards Supported**: USB 1.0, 1.1, and 2.0 protocols, with power delivery.
- **Image**: Illustrated in [USB 2 Standard receptacles.svg](https://commons.wikimedia.org/wiki/Special:FilePath/USB_connector_illustration,_to_scale,_grouping,_legacy,_USB_2_Standard_receptacles.svg), depicting Standard-A and B variants.
- **Different From**: Distinct from USB Micro, Mini, and Type-C receptacles, as well as USB 3.x variants.

## FAQs
### Q: What replaced the USB 2 Standard receptacle?
A: The USB 2 Type-C receptacle replaced all legacy USB Standard receptacles, including Standard-A and B, as a universal solution.

### Q: What is the difference between USB 2 Standard-A and B receptacles?
A: Standard-A receptacles are used on host devices (e.g., computers), while Standard-B receptacles are used on peripheral devices (e.g., printers).

### Q: Are USB 2 Standard receptacles compatible with USB 3?
A: USB 2 Standard receptacles support USB 1–2 speeds but lack USB 3.x capabilities, which require separate USB 3 Standard or Type-C connectors.

## Why It Matters
The USB 2 Standard receptacle played a critical role in standardizing USB connectivity before the USB-C era. It enabled consistent data transfer (up to 480 Mbps) and power delivery across devices, fostering interoperability between hosts and peripherals. As the predecessor to USB-C, it established foundational design principles for reversible, scalable connectors. Its legacy is evident in the widespread adoption of USB-A and B ports in pre-2010s devices, from computers to peripherals. Understanding this connector highlights the evolution of USB technology toward faster, universal solutions like USB-C.

## Notable For
- **Host-Peripheral Distinction**: Introduced the "A" (host) and "B" (peripheral) design paradigm for USB connectivity.
- **Backward Compatibility**: Supported USB 1.0/1.1/2.0 protocols, ensuring longevity across device generations.
- **Rectangular Shape**: Recognizable rectangular design with four pins, distinct from later Micro/Mini and Type-C forms.
- **Universal Replacement**: Fully superseded by USB-C, which eliminates the need for separate host/peripheral connectors.

## Body

### Overview
The USB 2 Standard receptacle is a class of legacy USB connectors defined in USB 1.0, 1.1, and 2.0 specifications. It includes two primary variants: **Standard-A** (host) and **Standard-B** (peripheral), designed for upstream and downstream connections, respectively. These receptacles were officially replaced by the USB Type-C receptacle, which unifies host and peripheral roles.

### Technical Specifications
- **Data Transfer**: Supports USB 1.0 (Low/Full Speed, 1.5–12 Mbps), USB 1.1, and USB 2.0 (High Speed, 480 Mbps).
- **Power Delivery**: Provides 5V power, with current limits dependent on device negotiation (typically up to 500 mA).
- **Pin Configuration**: Four pins (Vbus, D-, D+, GND) in a rectangular housing, with Standard-A featuring a flat plug and Standard-B a square-shaped plug.

### History and Legacy
- **Pre-C Era**: Dominated USB connectivity prior to the 2014 introduction of USB Type-C.
- **Deprecation**: Marked as legacy in USB-IF documentation, with USB-C recommended for new designs.
- **Cultural Impact**: The Standard-A receptacle became synonymous with "USB ports" on computers, while Standard-B was common on printers and external drives.

### Official References
- Defined in **USB 3.1 Legacy Cable and Connector Specification** (Revision 1.0) and **USB Type-C Specification** (Release 2.4).

## 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)