Simplex: Data communication in one direction only. Contrast to Full duplex , Half duplex.
单向：数据只作一个方向的传送。有别于全变向，半变向。
2
Telegraph repeater. One-way simplex, two-way simplex, or duplex operation can be specified.
电报中继器。可指定为单向单工、双向单工或双工运行。
3
Many traditional single simplex communication devices now can act as a duplex system under the help of voice activated module, which is actual voice activity detector.