Digital monitoring system, from video encoding, video transmission to control store all  belong to video surveillance system of digital signal. It is compared to analog control system. The evolution of video surveillance system has gone through four generations:
      The first generation: the whole simulation system: Analog camera + tape unit, has gone out of use. 
     The second generation: semi-digitalization systems: analog cameras +embedded DVR, this stage is characterized by conversion of an analog signal to digital signals stored in the hard disk, solved a big problem of the video store, since then, the surveillance market has been developing rapidly.
      Third Generation: quasi-digital system: Analog camera + digital video server (DVS) 
      Fourth generation: Full-digital system (our generation): full-digital system using network cameras can be seamlessly connected with other sub-systems, realize real digitalization.
      Network monitoring system has the following characteristics: 
      Forward-looking: The structure of analog control system determines that it can not avoid many limitations, for instance, it only can achieve online real-time viewing, and difficult for  remote monitoring. It is the trend that analog monitor must be replaced by network monitoring.
      Advanced: Network Camera as embedded real-time monitoring equipment, has simple network monitoring system structure, is easy to wire and construct. It can simultaneously convey multiple camera video signal with only a cable.
      Cost  effectiveness: While network camera is more expensive than analog camera, it can highlight its advantages in considering the entire system, especially large-scale network video surveillance system more than 100 channel, requiring simple equipment. System can realize centralized management through the back-end management software, eliminating a large number of devices compared the analog control system, such as expensive matrix, Quad processor, switcher, host for video changing to other network. Only for wire, it can save up to more than 70 percent of the cost a year. So it is usually of lower price to made large-scale monitoring system into network monitoring system than analog control system.
      Security: easier to manage the system, network monitoring system can grant to users of  vary classes by setting up different permission levels. Only the users of highest classes can set up and modify the whole system, only those have sufficient permissions can view the relevant video, greatly improve the security of the system.
      Use and maintenance are simple: the system is easy to install, simple to maintain. Simple system structure greatly reduces the chance of system failure, and can upgrades and maintain the system software through remote operation.
Good expansibility: when the system needs to expand, just add the appropriate front-end devices (such as network cameras, etc.), and without the needs of a wide range of modifying and changing systems. 
      Wide range of application: Regional monitoring, real-time image delivering by use of networks , such as offices, buildings, etc; inter-district remote monitoring, such as the chain enterprises, large-scale factory machine room, the far away elderly, children monitoring, public buildings, no man environmental monitoring, financial branch agency monitoring, traffic monitoring, false alarm identification and others.
       Unique digital network cameras
       The difference between digital network cameras and analog cameras:
These two products are both used for security monitoring. First, the fundamental difference is the method of video transmission, the signal of the former is digital, so transmitted by cable, which can easily achieve remote control, wherever the user is, as long as they connect Internet, they will be able to see the front-end video immediately . The signal of the latter is analog, only can see to where the video cable reached, it is difficult to achieve remote monitoring.
       The difference between digital network cameras and digital cameras:
       First, these two products are of different levels, the application values are quite different. The features of digital camera are simple, generally used for ********, network camera is a kind of powerful camera, generally used for security monitoring, video management, video conference etc. Second, the network camera connect to switches through network cable, after registration and log in, the video can be seen on the Internet, the monitoring ends are no need of computers, while the digital camera connect to computer by USB, and monitor side need a computer.