信号通信系统 [通信] signal communication system

有声信号通信 communicating by sound

可见信号通信 communicating by sight

信号通信手段 means of signal communications

简易信号通信 simplified signal communications ; simple signal communication

信号通信中心 signal center

呼号呼叫信号通信呼号 call sign

目视信号通信 VC ; Visual Communication

目视信号通信网 [通信] visual net