JT-C系列机车信号记录器对于辅助信息传输的接口是（）
A. RS-485
B. 8251串
C. RS-232
D. RS-422
查看答案
Which of the following is a typical data warehouse query?（）
A. What is this customers address?
B. Does this customer have any unpaid bills?
C. What is the balance in this customers account?
D. What are the total sales for each of the last 6 months?
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