Now smart home has become a commonplace problem. It is now recognized that one of the pain points of smart home is that the standards are not unified. Each manufacturer fights its own way. Manufacturers with small strength seek to produce single products with explosive models. Manufacturers also develop a unified home control system and need wiring. It is relatively troublesome and the price remains high.
Companies with large volume are building their own ecological platforms. We will not list the familiar Jingdong Weilian, Xiaomi, Haier u-home, Huawei, Meizu, Alibaba, etc. Today, we look at what is chaos and what is standard from a small USB interface.
I believe all the friends who read this article know what USB interface is. Now the most widely used connection buttons for computers, televisions, cameras and other electronic devices. Is it true that these things are born with USB? Of course not. Let’s take a look at the history of USB.
It is recorded that USB was an electronic interface jointly launched by Intel and other companies at the end of 1994. Before USB, there were b-5pin interface, b-4pin interface, b-8pin interface, b-8pin-2 * 4 interface, etc. at that time, after computers came out, they were not all USB interfaces, which could be described as five flowers and eight doors. When USB came out in 1994, it did not unify the market immediately, There have also been several rounds of development.
USB 1.0 appeared in 1996, with a speed of only 1.5mb/s (bits per second); In 1998, it was upgraded to USB 1.1, and the speed was greatly increased to 12MB / s. This standard interface can be seen on some old devices.
USB1.1 is a universal USB specification. The transmission rate of high-speed mode is 12mbps, and that of low-speed mode is 1.5mbps (b means bit). B / s generally represents bit transmission speed, and BPS represents bit transmission rate, which is equal in value. B / s and B / s, BPS (bytes per second) and BPS (bits per second) cannot be confused. 1MB / S (megabyte / s) = 8mbps (megabit / s), 12mbps = 1.5mb/s. Most MP3 interfaces are of this type.
USB2.0 specification evolved from USB1.1 specification. Its transmission rate reaches 480mbps, which is converted to 60MB / s, which is enough to meet the rate requirements of most peripherals. The enhanced host controller interface (EHCI) in USB 2.0 defines an architecture compatible with USB 1.1. It can drive USB 1.1 devices with USB 2.0 drivers. In other words, all devices supporting USB 1.1 can be used directly on the USB 2.0 interface without worrying about compatibility problems, and accessories such as USB cable, plug and so on can also be used directly.
The change brought about by using USB for printer applications is a significant increase in speed. The USB interface provides a connection speed of 12mbps, which is more than 10 times higher than that of the parallel port. Under this speed, the transmission time of printing files is greatly reduced. The USB 2.0 standard further improves the interface speed to 480mbps, which is 20 times the speed of ordinary USB, and greatly reduces the transmission time of printed files.
USB 3.0 the USB 3.0 promoter group, composed of Intel, Microsoft, HP, Texas Instruments, NEC, st-nxp and other industry giants, announced that the new generation USB3.0 standard formulated by the organization has been officially completed and publicly released. The theoretical speed of USB3.0 is 5.0gb/s. In fact, it can only reach 50% of the theoretical value, which is close to 10 times that of USB 2.0. The physical layer of USB3.0 adopts 8B / 10B coding mode, so the calculated theoretical speed is 4GB / s, and the actual speed needs to deduct the protocol overhead, which should be less on the basis of 4GB / s. It can be widely used in PC peripherals and consumer electronics.
USB 3.0 will be called “USB superspeed” in practical device applications, conforming to the previous USB 1.1 fullspeed and USB 2.0 highspeed. It is expected that commercial controllers supporting the new specification will be available in the second half of 2009, and consumer products have been on the market.
The unification of standards will take more than ten years. At the plenary session of ITU-T research group 5 (SG5) held in Geneva, Switzerland, on October 26, 2009, the framework standard of “power adapter and charger scheme for general mobile terminal and other ICT equipment” was discussed and adopted, and applied for approval. This actually means that the mobile phone charger standard will be unified all over the world.
Now we don’t have to look at computers. They must have USB interfaces. Mobile phone chargers are also USB interfaces, so they can be used with plug-in. The unification of standards has also reduced the price of products and, more importantly, promoted the development of the whole industry. In fact, the smart home is the same at the beginning. All princes play their own territory.
If smart home is popular, it is impossible for us to use one brand of electrical appliances in our home, let alone a set of systems. It must be the integration of various brands. The reason is very simple. Gree does a good air conditioner, but it doesn’t necessarily work as an induction cooker. Haier’s refrigerator is powerful, but it doesn’t necessarily work as a range hood. Now we need to have such a USB interface, Let any brand of electrical appliances at home can be interconnected, talk to each other, and finally understand our words. This is the key.