Application of Remote Video Technology in Network NC Processing Monitoring (3)
ATM (Asynchronous Transfer Mode) will become the main transmission mode of the next generation broadband network. The ATM network uses fixed cell and asynchronous methods to ensure the efficiency of transmission. It can do fixed bandwidth allocation, has high bandwidth, high efficiency and provides QoS guarantee. It is especially suitable for high-speed, real-time multimedia communication applications. ATM can achieve an exchange rate of up to 155-622 Mb/s. The use of ATM networks to connect real-time distribution systems has the advantage of reducing the host's capacity, thereby providing real-time services to the application while also supporting TCP/IP network protocols. IPOVER ATM technology, as shown in the figure: The logical subnet (LIS) is a combination of any host and router directly connected to the ATM network according to the connection requirements of the user and the network administrator. There is an ARP server in each LIS responsible for the resolution of the IP address and ATM address. IP packets can be transmitted on point-to-point ATM's permanent virtual channel (PVC) and ATM switched virtual channel (SVC). MCU (Multipoint Control Unit) The Multipoint Control Unit (MCU) is the primary control and forwarding device for video communication systems. Through the MCU, multiple manufacturing companies can join the conference system, so that the system has good scalability. The function of the MCU is to realize information control and exchange between terminals. Specifically: mixing a plurality of audio signals: selecting a desired one of the received video signals: mixing the video and audio signals transmitted to the respective users to form a composite output signal. There are two ways for the MCU to allocate information: one is the multicast mode, which means that the multimedia information of a certain user is simultaneously allocated to several users: The second is the bridge mode, which combines the multimedia information of multiple users and then allocates them to multiple Online users. New MCUs, such as Accord's MGC-100, use advanced technologies such as built-in gateway technology: multi-code conversion: dynamic split-screen technology: firewall solution technology. It can realize the interconnection of H.320 network and H.323 network. 6 Conclusion Remote video technology is a good collaborative tool used in network numerical control, which not only enables operators to understand the operation of CNC machine tools more comprehensively, but also provides an intuitive environment for remote monitoring and operation. At the same time, real-time video and audio transmission facilitates timely feedback of remote fault diagnosis and solutions. At this stage, it is an effective means to improve the agility of the enterprise. The system has passed the test on the campus network of the school, and has obtained clear and stable images at the transmission speed of 128kbps, 384kbps and 512kbps. Previous page
ATM access technology 
Figure 4 Logical Subnet (LIS)