How many types of USB interfaces are there?

There are several types of USB interfaces, categorized mainly by their connectors and cables. Here is a comprehensive list:

1. USB Type-A:

   • The original and most recognizable USB connector, used for upstream connections like computers and hubs.

2. USB Type-B:

   • A square-shaped connector used for downstream connections such as printers and external hard drives.

3. USB Type-C:

   • A modern, reversible connector used for both data transfer and power delivery, compatible with the latest devices.

4. Micro-USB:

   • Micro-A and Micro-B connectors are smaller and used primarily in mobile devices and some peripheral devices.

5. Mini-USB:

   • Mini-A and Mini-B connectors are older and were commonly used for smaller devices like cameras and MP3 players.

6. USB 3.0 and 3.1:

   • Type-A and Type-B connectors but with additional pins for faster data transfer (USB 3.0) and improved power delivery (USB 3.1) capabilities.

7. USB 4:

   • Uses the USB Type-C connector, offering even faster data transfer rates and improved compatibility with Thunderbolt 3 devices.

In summary, there are around 8 primary types of USB interfaces, each designed for specific applications and compatibility requirements.