A Class C EPIRB().
A. is primarily designed for vessels operating up to 50 miles offshore or on foreign waters
B. transmits a signal that can be detected by satellite
C. must be manually activated
D. operates in the medium and low frequency band
()是PLC的核心部件,它协调和指挥PLC的整个工作过程。
A. 软件
B. 存贮器
C. I/O单元
D. CPU
RNC上的接口控制信令单元为()
A. OMU
B. ICSU
C. RSMU
GB/T9445—2005标准规定,3级无损检测人员的基础考试的方式为()。