What are the devices that can be connected to a PC via USB?

Brief description of USB

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USB is an abbreviation of Universal Serial BUS, which means "Universal Serial Bus" in Chinese. It is not a new bus standard, but an interface technology applied in the field of PC. USB was jointly proposed by Intel, Compaq, IBM, Microsoft and many other companies at the end of 1994. However, it has not been widely used until recently. From November 11, 1994 published USB V0.7 version after the USB version of the development of many years, to the present has developed to 2.0 version, become the current standard expansion interface in the computer. Currently the motherboard is mainly used USB1.1 and USB2.0, the USB version of the good compatibility between the USB plug, USB with a 4-pin plug as the standard plug, using a daisy-chain form can be connected to all the peripherals, up to a maximum of 127 external devices can be connected to the bandwidth will not be lost. USB requires the host computer hardware, the operating system and peripherals to work in the three aspects of the support. The current motherboard are generally used to support the USB function of the control chipset, the motherboard is also installed on the USB interface socket, and in addition to the back panel of the socket, the motherboard is also reserved for USB pins, can be connected to the front of the chassis through the cable as a front USB interface for ease of use (note that in the wiring to carefully read the motherboard manual and connect the diagrams, must not be connected to the wrong equipment and damage). And the USB interface can also be achieved through a special USB cable to interconnect the two machines, and can be extended through the Hub more interfaces. USB has a fast transfer speed (USB1.1 is 12Mbps, USB2.0 is 480Mbps), easy to use, support for hot-swappable, connectivity, flexible, independent power supply, etc., can be connected to the mouse, keyboard, printer, scanner, The USB 2.0 is 480Mbps, easy to use, supports hot-swap, flexible connection, independent power supply and other advantages, can be connected to the mouse, keyboard, printer, scanner, camera, flash drive, MP3 player, cell phone, digital camera, mobile hard disk, external optical disk drive, USB network card, ADSL Modem, Cable Modem, etc., almost all of the external devices.

USB is an external bus standard that regulates how computers connect and communicate with external devices. the USB interface supports plug-and-play and hot-plug functionality for devices.

The USB interface can be used to connect up to 127 peripherals, such as mice, modems, and keyboards.

Since its introduction in 1996, USB has successfully replaced serial and parallel ports and is now one of the must-have interfaces for today's personal computers and a large number of smart devices.

USB uses a four-pin plug as the standard plug, and daisy-chains all of its peripherals together.

Versions of USB

First generation: USB 1.0/1.1 has a maximum transfer rate of 12Mbps. introduced in 1996.

Second Generation: USB 2.0 has a maximum transfer rate of up to 480Mbps. USB 1.0/1.1 and USB 2.0 interfaces are compatible with each other.

Third generation: USB 3.0 Theoretically 5Gbps Downward compatible with USB 1.0/1.1/2.0

usb applications:

With the rapid development of computer hardware, peripheral devices are increasing, keyboards, mice, modems, printers, scanners have long been known to the **** know that the digital camera, MP3 Walkman one after another. So many devices, how to access the personal computer?USB is based on this purpose generated.USB is a computer peripherals to connect standardized, single interface, its specifications are developed by Intel, NEC, Compaq, DEC, IBM, Microsoft, Northern Telecom contact.

The USB1.1 standard interface has a transfer rate of 12Mbps, but a USB device can only get up to 6Mbps of bandwidth. Therefore, if you want to connect an external hard drive to your PC, you can connect it to a 6x faster drive, but not much higher. If you want to play MPEG-1 VCD movies instantly, at least 1.5Mbps transmission bandwidth, which USB can do, but to complete the data volume of four times the amount of MPEG-2 DVD movie playback, USB may be very difficult, if coupled with the AC-3 audio data, the USB device is very difficult to realize the instant playback.

A USB port can theoretically support up to 127 devices, but that number is currently unattainable. In fact, for a computer, there are rarely more than 10 peripheral peripherals connected, so this number is sufficient for us.

Another significant advantage of USB is that it is hot swappable, which means that you can safely connect and disconnect USB devices while they are still powered on, making it truly plug-and-play.

However, not all Windows systems support USB; there are many different versions of Windows, and of those, only Windows 98 and above have good support for USB, while other versions of Windows don't have full support for it. For example, the retail version of Windows 95 does not support USB, and only the version of Windows 95 that was later bundled with a PC supports USB.

The current USB devices are widely used, but the more common one is the USB1.1 interface, which has a transfer speed of only 12 Mbps. For example, when you scan a picture of 40 Mbps with a USB1.1 scanner, it will take you 4 minutes to complete the scan. . This speed makes it very inconvenient for users who have several images to scan, and it requires a lot of patience to wait.

The user's needs are the driving force behind the development of technology, and vendors have similarly recognized this bottleneck. At this point, COMPAQ, Hewlett Packard, Intel, Lucent, Microsoft, NEC, and PHILIPS, the seven manufacturers jointly developed the USB 2.0 interface standard. USB 2.0 will be the data transfer speed between the device to increase to 480Mbps, than the USB 1.1 standard is about 40 times faster than, speed of the The biggest benefit to users is that it means they can use more efficient external devices, and peripherals with multiple speeds can be connected to the USB 2.0 line without worrying about bottlenecks in data transfer.

So if you're using a USB 2.0 scanner, it's a completely different story. Scanning a 40M image takes about half a minute and goes by in a blink of an eye, making it much more efficient.

And, USB 2.0 can use the same specifications of the original USB definition of the cable, the connector specifications are exactly the same, in the high-speed premise of the same to maintain the excellent characteristics of the USB 1.1, and, USB 2.0 devices will not be and USB 1.X devices in the *** with the same use of the time of the occurrence of any conflict.

USB2.0 is compatible with USB1.1, which means that USB1.1 devices can be used in conjunction with USB2.0 devices, but at this time, USB2.0 devices can only be used in full-speed mode (12Mbit/s). USB2.0 has high speed, full-speed, and low-speed operating speeds. USB2.0 has a high-speed, full-speed and low-speed three operating speeds, high-speed is 480Mbit/s, full-speed is 12Mbit/s, low-speed is 1.5Mbit/s. Full-speed and low-speed is designed to be compatible with the USB1.1, so when you buy and sell USB products you can not just listen to the business publicity USB2.0, but also to figure out whether it is high-speed, full-speed or low-speed devices. USB bus is a unidirectional bus, the main controller in the PC, the USB device can not take the initiative to communicate with the PC. In order to solve the problem of USB device intercommunication, the relevant manufacturers have developed the USB OTG standard, allowing embedded systems to communicate with each other through the USB interface, thus getting rid of the PC.

USB vs IEEE1394

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I. What are the main similarities between USB and IEEE1394?

Both are a general-purpose external device interface.

Both can quickly transfer large amounts of data.

Both have the ability to connect several different devices.

Both support hot-plugging.

Both can be used without an external power source.

Two, what are the differences between USB and IEEE1394?

The two transmission rates are different, the transmission rate of USB and IEEE1394 rate is really small compared to the USB transmission rate is only 12Mbps/s, can only be connected to the keyboard, the mouse and the microphone and other low-speed devices, while the IEEE1394 can be used to use the 400Mbap/s, can be used to connect the digital camera, scanner, and information appliances and other needs of high-speed rate. information appliances and other devices that require high speeds.

The structure of the two is different: USB must have at least one computer when connecting, and must need a HUB to realize the interconnection, the whole network can be connected to a maximum of 127 devices.

IEEEE1394 does not need a computer to control all the devices, and does not need a HUB, the IEEE1394 can be connected to multiple IEEE1394 networks with bridges, that is to say, in the case of a 63-degree IEEE1394 network, it is possible to connect the IEEE1394 network to a bridge. IEEE1394 can also connect other IEEE1394 networks with bridges to achieve unlimited connectivity after IEEE1394 has realized 63 IEEE1394 devices.

The intelligence of the two is different: IEEE1394 network can automatically reset the network when it adds or removes devices, and USB uses the HUB to determine the addition or removal of connected devices.

The two applications are different. USB has been widely used in all aspects, almost every PC motherboard set up USB interface, USB2.0 will further increase the scope of USB applications. IEEE1394 is now only used in audio, video and other multimedia aspects.

Front USB ports

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Front USB ports are USB expansion ports located on the front panel of a chassis. At present, the use of USB interface of various external devices more and more, such as mobile hard disk, flash drive, digital camera, etc., but in the use of these devices (especially often used in the mobile storage device) every time to drill to the back of the chassis to use the motherboard on-board USB interface is obviously inconvenient. Front USB port in this regard provides users with a good ease of use. Currently, front panel USB ports have become almost standard on chassis, and chassis without front panel USB ports are very rare.

The front USB port should be connected to the corresponding front USB pins on the motherboard (generally 8, 9 or 10 pins, two USB pairs, where each USB uses 4 pins to transmit the signal and power supply) using the USB cable supplied with the chassis in order to use it. When connecting the front USB interface must be carefully read the motherboard manual and chassis manual in advance of the content related to it, must not be connected to the wrong cable, otherwise it will cause damage to the USB device or the motherboard.

Additionally, when using the front USB port, pay attention to the problem of insufficient power supply to the front USB port, and when using a USB device that consumes a lot of power, use an external power supply or directly use the motherboard's on-board USB port on the back of the chassis in order to avoid the USB device from not functioning properly or from being damaged.

USB port hard drive enclosure

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The current mainstream, its biggest advantage is easy to use, support for hot-swap and plug-and-play. there are two standards of USB: one is the USB1.1 interface, which has a transfer speed of only 12Mbps, and the other is the USB2.0 interface, which has a transfer speed of up to 480Mbps. current motherboards on the The USB of the current motherboard all support USB1.1, but USB 2.0 only newer motherboards can support, buy according to the individual situation to choose the product, although USB2.0 downward compatible with USB1.1, but support USB2.0 interface mobile hard disk enclosure than USB1.1 to be more expensive.

Wireless USB

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Jeff Ravencraft, chairman of the USB Developers Forum and Intel's technology strategy officer, said wireless USB technology will help users connect devices such as printers, digital cameras, music players, and external disk drives to their PCs, freeing them from the complexity of cable connections. The wireless USB standard offers data transfer rates of up to The data transfer rate of the wireless USB standard is the same as the current wired USB 2.0 standard, which is 480M per second. The difference between the two is that wireless USB requires a wireless transceiver to be equipped in the PC or peripheral instead of a cable.

On the eve of the Intel Developer Forum, Ravencraft said that the first adopters of this standard will be external disk drives, digital cameras, and printers. And more and more products will start coming to market in the third quarter of this year.

In order for the wireless USB standard to be practical, some of the shortcomings of the technology must be improved. On Monday, the USB standards group announced the Wireless Alliance specification, which ensures that only certified computers and peripherals can be connected via wireless USB.

Ravencraft added that the USB standard has been widely used to connect digital cameras, scanners, cell phones, PDAs, DVD recorders, and other devices to PCs. The Wireless Alliance specification, on the other hand, details how PCs and peripherals can be connected via wireless USB, with up to 127 peripherals connected to a single PC at the same time.

The Wireless Alliance specification specifies two methods for establishing a connection. The first method is that the PC and the peripheral are first connected with a cable, and then a wireless connection is established for later use. The second method is that the peripheral can provide a string of numbers that the user enters into the computer when establishing the connection.

Wireless USB uses ultra-wideband technology to communicate. While the current 802.11g protocol for wireless LANs uses a small band of frequencies located near 2.4GHz for communication, ultra-wideband technology uses a band of frequencies from 3.1GHz to 10.6GHz for communication. The signal levels in ultrawideband are low enough that the effect of ultrawideband signals is similar to noise for other wireless communication technologies.

The most widely used technology for wireless networking today is the IEEE 802.11 standard, also known as Wi-Fi, which is promoted by Intel and is widely used in laptops and even in some Nikon and Canon digital cameras. Wireless USB is a completely different technology, and because it is relatively simple to implement and consumes half the power of 802.11, many manufacturers prefer to use wireless USB.

Ravencraft said that the key to adopting 802.11 in high-end cell phones and digital cameras is to address battery life. And vendors are finding that ultra-wideband technology is the best way to address this issue.

Within 10 feet of a computer, a wireless USB device's transfer rate will remain at 480 Mbps, and if it is within 30 feet, the transfer rate will drop to 110 Mbps. However, as the technology evolves, the wireless USB transfer rate will be more than 1Gbps or faster.

Currently ultra-wideband technology can be used not only in wireless USB connections, but also in Bluetooth and IEEE's 1394 FireWire connections and even WiNet short-range connections.

The different interfaces and cables of USB

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With the massive popularity of various digital devices, especially MP3s and digital cameras, we are gradually surrounded by more and more USB devices. However, although these devices are all using the USB interface, the data cables of these devices are not exactly the same. These cables are the same at the PC end, but when it comes to connecting to the device end, there are a variety of different interfaces that are often used for size considerations.

The vast majority of digital product cables have the same connector on the other end of the cable, except that the one that connects to the PC is the same, and the other end of the cable follows a standardized specification.

USB is a unified transmission specification, but there are many kinds of interfaces, the most common is the kind of flat we use on the computer, which is called the A-port, there are four wires inside, according to who plugged into who is divided into male and female interfaces, generally on the line with the male port, the machine with the female port.

●USB A-type male port

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The above link picture is the most common USB A-type male port

Common Mini B-type 5Pin connector:

The next is the most common connector on the digital products. The Mini B connector is usually used due to the size limitation of digital products, but there are many types of Mini B connectors.

●Mini B 5Pin

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The image linked above is a diagram of a Mini B 5Pin connector

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The image linked above is a diagram of a Mini B 5Pin connector. A picture of the Mini B 5Pin connector

This connector can be said to be the most common type of connector, which is winning more and more favor from manufacturers due to its excellent anti-wrong-way performance and compact size, and is now widely used in card readers, MP3 players, digital cameras, and portable hard drives.

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The image linked above shows a Mini B-type 5Pin connector on the Sony F828

The devices that use this connector now include Sony cameras, camcorders, and MP3s, Olympus cameras and voice recorders, Canon cameras, and HP digital cameras. digital cameras, to name a few, and the list is quite extensive.

Common Mini B 4Pin connectors:

In addition to the most common Mini B 5Pin connectors we've seen, there are many other Mini B connectors, some of which are more common.

●Mini B 4Pin

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Above: Mini B 4Pin connector

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Above: Mini B 4Pin connector adapter

. Adapter cable for 4Pin connector

This connector is commonly used in the following brands of digital products: Olympus C and E series, most of Kodak's digital cameras, Samsung's MP3 products (e.g., Yepp), Sony's DSC series, and Compaq's IPAQ series products.......

Fuji Mini B-type 4Pin Flat Interface:

There is another form of Mini B-type 4Pin, and that is Mini B-type 4Pin Flat.As the name suggests, this interface is flatter than Mini B-type 4Pin and is more widely used in devices.

●Fuji Mini B 4Pin Flat

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Above: Mini B 4Pin Flat connector

This connector is very similar to the MINI B 4pin mentioned earlier, but this connector is much flatter, and takes up less space. The connector is very similar to the MINI B 4-pin

This connector is commonly found on Fuji's FinePix series, Casio's QV series cameras, and Konica products.

We've seen more Fuji machines with this interface, and almost all of the older models have this interface. It's worth noting, though, that Fuji has dropped this interface in favor of the Mini B 5Pin on its latest S5000 and S7000.

Nikon's exclusive, Mini B 8Pin connector:

In addition to the 4- and 5-pin Mini B connectors, there's also an 8-pin connector, which is much less common on other devices and usually found on digital cameras. Round) type, and a flat connector with a 2×4 layout.

●Mini B 8Pin

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Pictured: Mini B 8Pin connector

This type of connector applies to the equipment, as far as I know, at present, only the Nikon Coolpix 775 a model of the product to use this interface.

●Mini B 8Pin Round

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Pictured here is the Mini B 8Pin Round connector

This connector is the same as the normal type. Compared with the previous normal type, the original D-type connector has been changed into a round connector, and a bump has been designed on one side to prevent misplugging.

This type of connector can be found on some Nikon digital cameras, and is more common on the CoolPix series. While Nikon has stuck with this connector, the most popular Mini B type 5Pin connector has also been adopted in some newer models such as the D100 and CP2000.

Almost universal, the 8Pin 2×4 connector:

In addition to the Mini B 5Pin connector we saw earlier, I'm sure you're also familiar with the following connector, which was also once quite popular.

●Mini B 8Pin 2×4

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Pictured here is the Mini B 8Pin 2×4 connector

This is a more common connector. This is a relatively common interface, for example, we are familiar with iRiver's famous MP3 series, which is known as "Audio-Technica" 180TC, as well as many other products in the series are used in this interface. This interface has a wide range of applications, but since the 3XX series of iRiver's switch to the Mini B 5Pin interface, this specification is clearly not as eye-catching as the Mini B 5Pin.

Introduction to USB 3.0

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Intel, along with industry-leading companies, has joined forces to form the USB 3.0 Promotion Group, which aims to develop ultra-efficient USB interconnections at speeds up to 10 times faster than those available today. The technology was developed by Intel, along with Hewlett-Packard (HP), NEC, NXP Semiconductors, and Texas Instruments***, for applications including fast, synchronous, instantaneous transfers of personal computers, consumer and mobile products. With the growing popularity of digital media and the ever-increasing size of files being transferred - up to and including 25GB - fast, synchronous instantaneous transfers have become a necessary performance requirement.

USB 3.0 is a backward-compatible standard that combines the ease of use and plug-and-play functionality of traditional USB technology. The goal of this technology is to introduce products that are more than 10x faster than current levels of connectivity, utilizing the same architecture as wired USB. In addition to optimizing the USB 3.0 specification for lower power consumption and greater protocol efficiency, USB 3.0 ports and cables enable backwards compatibility as well as support for future fiber optic transmissions.

"USB 3.0 will logically become the next generation of the most ubiquitous wired interconnect for personal computers," said Jeff Ravencraft, technology strategist at Intel. "The digital age requires high-speed performance and reliable interconnections for the massive amounts of data transferred in everyday life. data volumes. usb 3.0 is well positioned to meet this challenge and continue to deliver the USB ease-of-use experience that users have grown accustomed to and continue to expect."

Intel started the USB 3.0 Promotion Group with the hope that the USB Design Institute (USB-IF) would serve as the industry association for the USB 3.0 specification. The full USB 3.0 specification is expected to be available in the first half of 2008, and USB 3.0 will initially take the form of discrete silicon.

The USB 3.0 Promotion Group, which includes Hewlett-Packard, Intel, NEC, NXP Semiconductors, and Texas Instruments, is committed to preserving the already existing USB device driver infrastructure and investment, the look of USB, and the ease-of-use, while continuing to build on the functionality of USB as a superior technology.

"Our support for USB 2.0 and wireless USB technology underscores HP's commitment to providing our customers with a reliable way to interconnect peripheral devices," said Phil Schultz, vice president of HP's Consumer Inkjet Solutions, Printing & Imaging. Schultz said, "Now with USB 3.0, we're creating an even better experience for our customers when printers, digital cameras and other peripherals are interconnected with their PCs."

"Intel has been at the forefront of the industry in the development and adoption of both generations of USB technology, which is now the most popular peripheral interface for computing and handheld electronics," said Patrick Gelsinger, senior vice president and general manager of Intel's Digital Enterprise Business Unit. ) said, "As the market evolves to support customer needs for storing and transferring huge amounts of data, we want to develop third-generation USB technology that can leverage existing USB interfaces and optimize them to meet those needs."

"NEC has been a supporter of USB technology since the first installation of wired USB," said Katsuhiko Itagaki, general manager of NEC Electronics' SoC Systems Division, "and now it's time to further develop this already successful connected interface to meet the market's higher demand for huge data transfer speeds to minimize user wait times."

"NXP is pleased to be working with other top companies to advance the world's leading interconnect technology to meet the needs of next-generation peripherals," said Pierre-Yves Coulson, director of strategy and business development at NXP Semiconductors' Business Line Connected Entertainment. As a leading provider of USB semiconductor solutions, NXP is committed to driving the standardization and adoption of SuperSpeed USB," said Pierre-Yves Couteau, Director of Strategy and Business Development at NXP Semiconductors."

"With the proliferation of high-speed USB within a variety of market segments, including personal computing, consumer electronics, and mobile, we anticipate that USB 3.0 will quickly replace USB 2.0 ports as the de facto standard for high-bandwidth applications," said Greg Hantak, vice president of Worldwide ASIC at Texas Instruments. Greg Hantak, vice president of ASICs at Texas Instruments Worldwide, said, "Texas Instruments is very excited that the superior performance of USB 3.0 will further expand the application areas of USB and deliver a better user experience."

About the USB Design Institute (Universal Serial Bus Implementers Forum)

The USB Design Forum (USB-IF), a not-for-profit organization, was founded to support the development and proliferation of USB technology. Through its logo and certification programs, the USB-IF provides assistance in the development of high-quality, compatible USB devices, and the USB-IF strongly promotes the benefits of USB and the quality of the products it certifies.