Intrinsically safe environments like this petrochemical plant -- you can't use RF, it may generate antenna sparks, but you can use light -- you see plenty of light there.
自然而然地保护了环境 在那些石化工厂里 你不能用RF, 它会在天线上产生火花， 但它可以用光，你能看到许多的灯光在那．