11．RS—232标准接口电路采用

A．同步方式                                                        B．开放型

C．平衡型                                                           D．非平衡型

12．400MHz电波信号属

A．微波                                                               B．长波

C．中波                                                               D．短波

13．用数字量多路开关SN74150采集遥信信号时，欲使W=E14，数据选择端ABCD应为

A．0111                                                               B．1110

C．1101                                                               D．1011

14．(15，7)循环码的全部许用码组有

A．256个                                                            B．129个

C．127个                                                            D．128个

15．调度员尽力维护子系统发电、用电平衡时属

A．正常状态                                                        B．紧急状态

C．恢复状态                                                        D．瓦解状态