With the development of interface, the era of digital home network is bound to come

Digital home network It is a network connecting digital appliances, and digitization is its connection mode. In the digital interface, there are 1394, USB, PCI Express and DVI / HDMI wired, UWB and WLAN wireless. Although at present, no technology can undertake the establishment alone Digital home network Overall ability, but what we can see in the future is their organic combination.

1394 bus is an ideal digital interface.

1394, namely IEEE1394, currently has three relevant standards:

1. 1394-1995. It defines a 6-pin cable and socket, which can be seen on several desktop computer motherboards. The 6 pins have two pairs of gap wires and power supply. The host needs to provide 1.5a/12v current, so it can only be used in desktop computers. Apple's registered FireWire trademark is common in this application.

2. 1394a-2000 is developed on the basis of 1394-1995. It adds the definition of 4-pin cable and socket, which can provide power to other devices without providing power, which is very suitable for consumer electronic products. Sony first used the interface on its digital camera products, with the trademark i.LINK. Moreover, 1394a is an expansion of 1394-1995, and now only 1394a is mentioned. 1394a requires stp5 cable, i.e. five kinds of twisted pair with shielding layer, with transmission distance of 4.5m and transmission speed of 100Mbps, 200Mbps and 400Mbps.

3. 1394b-2002.1394b standard is formulated from two aspects. In the PC industry, the external storage capacity of computers is increasing and faster transmission speed is required. 1394b increases the transmission speed to 800Mbps, 1600mbps and 3200mbps; In the field of consumer electronics, it is necessary to connect household appliances to the Internet with longer transmission distance. 1394b provides the transmission distance to 100 meters and provides more cable options.

Five kinds of unshielded twisted pair cables are actually five kinds of ordinary network cables. Now the specifications supporting s1600 are formulated, which is convenient and affordable in the family.

1394 adopts peer-to-peer transmission mode and the principle of fair competition. The equipment (nodes) of the bus will also send data to the bus without host control. It is very suitable for the characteristics of consumer electronic products. 1394 supports asynchronous transmission and isochronous transmission, and can be inserted immediately. 1394b supports closed-loop connection, which is more user-friendly. 1394 adopts a layer by layer processing mode, in which the physical layer and link layer are related to hardware, and the transport layer and application layer are related to software, which is conducive to engineers' design.

USB2.0 is an ideal choice for connecting PC and external devices.

There are many outward expansion interfaces of PC. in its development stage, there are parallel port, serial port, PS-2, infrared, ISA, PCI, etc. we call these interfaces traditional interfaces. The development of traditional interface has become the bottleneck of the system today. It is slow, there is no unified standard, high cost and occupies space. It needs convenient, concise and standardized interface. USB meets these needs.

USB is the abbreviation of universal serial bus. The current version is 2.0.usb2.0. It supports three transmission speeds: low speed (1.5mbps), full speed (12mbps) and high speed (480mbps). Traditionally, some people call USB that supports low speed and full speed USB1.1. In fact, it should not be called USB1.1 today, but full speed USB2.0.

USB adopts the host architecture, and the host controls all data transmission. It is very suitable for the connection between PC and peripherals. PC is the host. PC's powerful processor and a large amount of storage space can easily realize the hardware and software of the main controller. Peripherals only need to realize their own functions, simplify the design and reduce the cost.

A USB root interface can support 127 external settings. If the USB port of the host is not enough, you can use the hub to expand. The hub can have up to 5 layers, and the cable length between each layer can reach 5m. At present, many chipsets provide 8 USB root interfaces, which can basically meet the expansion requirements of computer external devices.

The main reason for USB is that there is no direct communication between external devices and external devices, so it is not suitable for the connection of consumer appliances. The USB host also needs to provide 500mA current, which is not suitable for the connection of handheld devices, which is the main reason for the emergence of usbotg standard.

Usbotg facilitates the connection of handheld devices.

Driven by mobile phone manufacturers such as Nokia and Motorola, the industry has formulated usbotg standards. OTG is the abbreviation of on the go.

Usbotg can be simply understood as a simplified USB main controller, which only needs to provide limited main control functions and does not need to have all main control functions like the main controller of PC. The minimum current usbotg needs to provide is only 8Ma, which is particularly important for mobile phones and PDA battery powered handheld devices. Desktop devices can also provide greater current when reading USB.

Usbotg realizes point-to-point connection, but it can only communicate between two devices and can not realize network function. Therefore, usbotg is a supplement to USB standard and can not replace 1394 connection between consumer appliances.

PCI Express revolutionized 3C convergence.

Today, with the development of PC, the CPU clock is faster and faster, and the PCI bus has reached the bottleneck period. The simple method of clock acceleration and data line widening can not meet the demand, especially in such a crowded and complex environment inside the PC. Because it is a parallel bus, speeding up the clock and expanding the data line will bring unsolvable electromagnetic radiation interference.

PCI Express is a serial bus, which adopts the method of differential data line. The input and output are a pair, called a pair of lanes, represented by x1. The transmission speed of input and output has reached 2.5Gbps. You can increase the number of lanes as needed. For example, replace the AGP bus of the graphics card with x16 and use X4 between the north and South bridges. These will be seen on new desktops and laptops.

PCI Express is the continuation and inheritance of PCI, and the software is compatible, so the system upgrade only needs to upgrade the hardware part.

DVI / HDMI connection display.

DVI refers to digital video interface, HDMI is high-definition multimedia interface, DVI only supports video signal, and HDMI also supports audio signal. DVI / HDMI realizes parallel / parallel conversion, converts parallel audio signals into parallel TMDS signals at the transmitting end, and restores TMDS signals into audio signals at the receiving end. Here, audio signals refer to uncompressed original signals.

DVI / HDMI supports the resolution of uxga, which exceeds the resolution required by HD TV. DVI can use HDCP to provide content protection, and HDMI itself contains the core of HDCP. Based on these two factors, DVI or HDMI with HDCP has been mandatory by the FCC of the United States to include electronic products related to HD TV, such as HD TV, cable set-top box, DVD player, etc. Europe, Japan and South Korea also have similar requirements soon. China may first take DVI interface as an option.

DVI / HDMI is a point-to-point connection. Its application range is relatively single and can only be used for products related to display screen. Therefore, it belongs to terminal interface in digital home network.

The prospect of wireless transmission is good.

At present, the common wireless transmission methods are Bluetooth, WLAN and UWB. Among them, WLAN is suitable for high-speed data network, and UWB is suitable for high-definition audio and video signal transmission and short-distance high-speed data synchronization. Bluetooth is limited by its low transmission speed, so it can't find more positioning points in the market.

With the improvement of semiconductor technology, the anti-static ability of the chip decreases. The interface technology with hot plug function requires good anti-static design, and the electrical equipment itself also needs good grounding. If the two are not ideal, there is a high possibility of damaging the chip during hot plug, which may damage the whole system. The biggest advantage of wireless transmission is to get rid of the shackles of cables without similar troubles.

The application prospect of wireless transmission, especially UWB technology, is very broad. In the future, it will replace wired connection technology, or the two will share equally. We will wait and see. However, no matter what technology and interface are adopted, the era of digital home network is bound to come.

Shenglan Technology Co., Ltd_ It focuses on the production of electronic connectors and research and development of precision components. Its products are widely used in consumer electronics, new energy vehicles, USB, 5g and other fields. Its industrial lines cover the Pearl River Delta, Southeast Asia and other regions. It has established long-term strategic cooperation relations with well-known enterprises such as Foxconn, Lixun precision, Huawei, Xiaomi, TCL, Hitachi Group, BYD and Great Wall Motors, with IATF 16949, ISO9001 ISO14001, QC080000 and other system certification and product safety certification, and provide professional connection and manufacturing solutions for the industry http://jctc.com.cn/