With the development of information and communication technology in China, a stable network timing system with fast transmission time and high accuracy is particularly important. Because more BIOS devices are used in the market, this may cause delays, errors and other errors. This article will give a brief introduction to the network time service system.

The timing of the network time service system is based on the NTP protocol. The whole network configuring one or more dedicated NTP network time servers that get standard time information from the satellite to all the time users in the network. In some specific occasions, the network timing system not only refers to the network time server, but also the network sub clock that obtains time information from the time server. Usually, they are widely used in airports, schools, hospitals, gymnasiums and other places because they need intuitive display of precise information on days, weeks, and hours.

The overall design idea of the network time service system is as follows:

1, conscientiously implement the relevant "norms" and "standards" promulgated and implemented by the state, so that the design does not deviate from the standardization and standardization of the track, thereby ensuring the design level and quality.

2, system design should be carried out in accordance with the principle of "reliable, practical, advanced and economical".

3, efforts should be made to reduce project costs and maintenance costs while meeting the functional requirements.

4. The system is easy to operate, reliable, easy to expand and maintain, and software has the ability to improve.

5. The system meets the field conditions and environment.

When designing the time service mode of the whole time service system, it is recommended that the TCP/IP mode should be preferred. It has the following advantages:

1) the IP sub clock system makes the system simpler. Expansion only needs to increase the number of network points.

2) management is simpler and more humane. Physically distributed and logically centralized.

3) adopt the standard TCP/IP protocol, it is safe and reliable, and the system compatibility is strong. It can be compatible with the standard equipment of various manufacturers and can be seamlessly integrated with other systems.

4) the sub clock IP address can be used to locate the clock accurately, so as to determine the fault and maintain it conveniently.

The sub clock system corresponding to the traditional RS485 bus mode has the following problems:

1) upgrading and expansion is difficult. Every new node needs to be added at the same time, and the ports corresponding to the master clock will lead to difficulties in the expansion and upgrading of the system.

2) difficult to manage. RS485 based analog sub clock system, complex implementation of the project, too many stacked equipment, resulting in increased failure rate. And it is difficult to achieve effective and effective management.

3) poor standardization. The RS485 simulation subsystem uses a lot of private technology, unreliable and poor standardization, and is difficult to integrate with other systems and manufacturers.

4) lack of automatic positioning methods for clock and terminal equipment, failure needs manual investigation and maintenance complex.

It is easy to see from some customers' demand for time service system that some of the manufacturers' online time service technology has remained in the traditional design way many years ago. The whole network timing system separates the master clock, the server and the receiver. This method has many limitations, such as a large number of devices, easy to make mistakes, and high input costs. It is difficult to install and debug and maintain later. Once the above equipment is wrong, all of the following will be affected. At present, the mainstream time service manufacturers have broken through this limitation, integrating the clock, server, time code distributor and receiver into a device such as SYN2151 NTP network time server.

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