USB完整发展史：从1.0到USB4 v2.0
USB发展27年：从12 Mbps到120 Gbps，从Type-A到Type-C。
## Timeline
| Year | Standard | Speed | Connector |
|---|---|---|---|
| 1996 | USB 1.0 | 12 Mbps | Type-A/B |
| 2000 | USB 2.0 | 480 Mbps | Type-A/B/Mini/Micro |
| 2008 | USB 3.0 | 5 Gbps | Type-A (blue) |
| 2013 | USB 3.1 Gen 2 | 10 Gbps | Type-A/C |
| 2014 | USB-C connector | — | Type-C |
| 2017 | USB 3.2 Gen 2x2 | 20 Gbps | Type-C only |
| 2019 | USB4 v1.0 | 40 Gbps | Type-C only |
| 2022 | USB4 v2.0 | 80/120 Gbps | Type-C only |
## Key Turning Points
1. **USB 2.0 (2000)**: Made USB the default for everything
2. **USB 3.0 (2008)**: 10x speed jump enabled external SSDs
3. **USB-C (2014)**: Reversible, universal connector
4. **USB4 (2019)**: Merged Thunderbolt 3 into USB standard
## The Naming Disaster
USB-IF has renamed standards multiple times. USB 3.0 became USB 3.1 Gen 1, then USB 3.2 Gen 1. This confusion has led consumers to distrust USB branding and rely on speed numbers (5/10/20/40 Gbps) instead.