About USB 3.1 #
USB 3.1 is a newer USB specification, initiated by major companies such as Intel. Data transfer speeds can go up to 10Gbps with this specification. Compared to USB 3.0 technology, the new USB technology uses a more efficient data encoding system and provides over double the effective data throughput. It is fully backward compatible with existing USB connectors and cables.
- USB 3.1 is compatible with existing USB 3.0 software stacks and device protocols, 5Gbps hubs and devices, and USB 2.0 products. USB 3.1 has three types of connectors, namely Type-A (Standard-A), Type-B (Micro-B), and the Type-C standard. Type-A is currently the most widely used interface, while Micro-B is mainly used in devices like smartphones and tablets. The newly defined Type-C is primarily aimed at thinner and more slender devices.
- Type-C significantly reduces its physical footprint, making it more suitable for small and lightweight handheld devices. Type-C will replace the Micro-AB connector (supporting direct USB device-to-device communication without the need for a host system), as well as the standard Micro-USB connector. Type-C, similar to the Apple Lightning connector, can be inserted in either orientation, making it more convenient than the existing Micro-USB. While Micro-USB has a mechanism to prevent reverse insertion, the benefit of being reversible allows for smooth connections in all situations. Additionally, Type-C also offers improved electromagnetic interference and RFI mitigation features.
Transfer Speed and Encoding Standards #
To accommodate high-speed applications on various devices, USB has seen significant progress in speed, starting from version 1.0 (1.5Mbps), 1.1 (12Mbps), 2.0 (480Mbps), and then 3.0 (5Gbps). Looking ahead to future demands, the new USB 3.1 interface will double the bandwidth to 10Gbps. It’s worth noting that the encoding rate is also being increased once again.
| USB Standard | Max Transfer Speed |
|---|---|
| USB 2.0 | 480 Mbit/s |
| USB 3.0 | 5 Gbit/s |
| USB 3.1 | 10 Gbit/s |
USB 3.0 uses 8b10b encoding, meaning that out of every 10 bits transmitted, only 8 bits contain actual data, while the remaining 2 bits are used as check codes. This results in a 20% (2/10) loss in overall bandwidth due to encoding. In contrast, the new USB 3.1 utilizes 128b/132b encoding, where only 4 bits are used as check codes within 132 bits of data. This significantly reduces the transmission loss to 3% (4/132). Therefore, USB 3.1 not only increases bandwidth but also improves transmission efficiency.
Furthermore, compared to Thunderbolt, both USB 3.1 and Thunderbolt 1 offer the same 10Gbps speed. While Thunderbolt 2 provides 20Gbps, it essentially combines two independent 10Gbps channels from Thunderbolt 1 into a single 20Gbps unidirectional channel, rather than bidirectional. In this regard, once USB 3.1 devices are officially on the market, they will still maintain a significant advantage in terms of bandwidth speed and widespread application.
Power Supply Standards #
Compared to USB 2.0’s 5V/0.5A, USB 3.0 provides a power supply of 5V/0.9A. However, people still desired greater power delivery capabilities. As a result, USB 3.1 (SuperSpeed+) increased the maximum allowable power standard to 20V/5A, delivering up to 100W of power. It’s important to note that Type-C is just an optional interface type that came along with the USB 3.1 standard. It doesn’t mean that all USB 3.1 interfaces are Type-C, and not all Type-C interfaces are necessarily USB 3.1. In fact, interface standard versions and types can be mixed and matched as needed: USB 3.1 Type-C, USB 3.1 Type-A, USB 3.0/2.0 Type-C, USB 3.0/2.0 Type-A, and so on—it depends on what manufacturers require.
Audio-Visual Transmission Standards #
USB 3.1 introduces USB A/V audio-visual transmission. Using USB for video transmission offers significant convenience. Besides the widespread availability of USB interfaces, it eliminates the need for an additional power cord, as USB (the USB Working Principle) can provide power directly. For instance, the ASUS MB168B+ 15.6-inch portable monitor connects via USB 3.0, although it supports up to Full HD resolution. The new USB AV 3.1 offers a bandwidth of 9.8Gbps and can support 4K display resolutions, reaching up to 4096 x 2304 @ 30FPS, on par with HDMI 1.4 specifications. USB AV also supports HDCP image encryption technology, and with enhanced power supply, larger-sized monitors can potentially display 4K resolution through USB AV 3.1. Additionally, existing devices and monitors can utilize USB AV adapters to transmit audio and video through USB cables. If USB AV becomes widespread, it has the potential to bring significant convenience to our lives and may even replace other display interfaces, becoming the most practical audio-visual transmission solution.
What are the advantages of USB 3.1 for smartphones? #
Enabling Faster Charging for Smartphones #
With the power supply standard raised to 20V/5A and 100W power delivery, USB 3.1 can significantly enhance the charging speed of devices, including smartphones. It can also provide power to laptops, projectors, and even televisions with higher power requirements. This is why Apple’s latest MacBook only needs a single built-in USB Type-C port to fulfill both power delivery and data transfer needs.
Higher Data Transfer Speeds #
Since USB 3.1 supports transfer rates of up to 10Gbps, it greatly enhances data transfer speeds for smartphones. This is highly advantageous for the development of smartphones. For instance, as more and more smartphones support 4K video recording, which results in larger video files, faster data transfer speeds become essential.
Versatility #
Clearly, a universal interface is what small devices like smartphones and tablets require, as it greatly enhances device connectivity. Currently, it appears that Type-C in USB 3.1 has the highest potential to become the future connectivity standard, offering an integrated solution for data transfer, peripheral connection, and display output.
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