Let's Talk About USB Interfaces~ Due to the confusing naming conventions set by USB-IF, many people struggle to differentiate between various USB versions. Let’s sort it out clearly.

I. USB Transmission Standards

Since the release of USB 1.0 in 1996 by the USB-IF (USB Implementers Forum), the USB standard has evolved through several versions: USB 1.1, USB 2.0, USB 3.0, USB 3.1, and USB 3.2. In 2019, USB-IF introduced the latest USB4 standard, setting new benchmarks for USB interfaces.

After the third renaming in 2019, the naming structure has finally settled as follows (see the diagram):

Important Note for Purchases

When buying USB drives or hard disks, pay close attention to the actual standard. For example, some devices claim to support USB 3.2, but they are actually USB 3.2 Gen 1, which is essentially the same as the original USB 3.0 standard. Each standard supports different maximum transfer rates, so clarity is crucial.

II. USB Interface Types

USB interfaces come in three main types:

1. Standard USB

2. Mini USB

3. Micro USB

1. Standard USB Interface

This is further divided into Type-A and Type-B, as shown below:

• Type-A: The most common USB interface in daily life, used in devices like mice, keyboards, and flash drives.

• Type-B: Often found in printers and specialized monitors.

USB 2.0 vs. USB 3.0:
The distinction between these standards can often be made by the color of the interface (blue for USB 3.0).

2. Mini USB Interface

A smaller version of the standard USB, featuring an additional ID pin to enable OTG (On-The-Go) functionality, allowing device-to-device data transfer without a host.

• Mini-A and Mini-B are its two variants.

Mini USB is commonly used in compact devices like MP3 players, MP4 players, radios, and some older mobile phones.

3. Micro USB Interface

A successor to the Mini USB, it uses stainless steel for its CONNECTOR, offering 10,000 plug/unplug cycles. While maintaining nearly the same width as Mini USB, its height is halved, making it more compact.

• Comes in Micro-A and Micro-B types.

Micro-B is widely recognized as the charging and data port for early smartphones (except Apple devices). With the release of USB 3.0, Micro-B evolved into a new design commonly seen in USB 3.0 external hard drive enclosures.

4. Type-C Interface

Introduced in recent years, Type-C offers the benefit of being reversible, eliminating the frustration of incorrect insertions.

• Statistical Fun Fact: The average person wastes 30 minutes per year struggling to insert USB plugs correctly. With Type-C, you can get it right on the first try!

The USB4 standard exclusively supports Type-C interfaces, adopting the Thunderbolt protocol (developed by Intel). This protocol features fast speeds, strong power delivery, and compatibility with multiple interfaces/protocols such as Thunderbolt, USB, DisplayPort, and PCIe.

Type-C is clearly the future of USB interfaces.

III. USB Transmission Standards and Interfaces

Finally, here’s a summarized diagram to show the relationship between USB transmission standards and interfaces for your reference!