Answer: A, B.
Answer analysis: When discussing the description of the synchronous control system of the display screen, we need to analyze each option one by one:
A. The control system is divided into synchronous and asynchronous types:
- This description is correct. The display control system can indeed be divided into synchronous control systems and asynchronous control systems. Synchronous control systems usually rely on computers or other signal sources to send display content in real time, while asynchronous control systems can work independently without real-time signal sources and play pre-stored content through built-in storage media (such as SD cards, USB flash drives, etc.).
B. The maximum load of a single network port is about 650,000 pixels:
- This description may need to be judged according to the specific control system and hardware configuration. In general, the load capacity of a single network port will be affected by factors such as network bandwidth, control system processing power, and display pixel density. 650,000 pixels as a rough value may be feasible in certain specific configurations, but not all synchronous control systems can reach this level. However, for the purpose of answering this question, we can assume that this description is correct in a certain situation, although it may not be absolutely universally applicable.
C. The synchronous system can work offline:
- This description is wrong. A synchronous control system requires a real-time connection to a signal source (such as a computer) to receive and display content, so it cannot work offline. In contrast, an asynchronous control system has the ability to work offline.
D. Synchronous systems cannot publish cluster information:
- This description is also wrong. Synchronous control systems are fully capable of supporting cluster information publishing. Through appropriate network architecture and control system configuration, multiple display screens can be connected to a synchronous control system to achieve synchronous publishing and display of cluster information.
In summary, the correct descriptions are A and B (although B is somewhat conditional). However, if you have to choose the most accurate and universally applicable description, then A "control systems are divided into synchronous and asynchronous types" is undoubtedly correct. But if you consider the possibility of B in a specific situation, we can also think it is correct (although not absolutely). But in the context of this question, we focus more on universality and accuracy, so we finally choose A as the correct answer. However, please note that in actual situations, the description of B may also be true under certain conditions.