232直接转成全双工（4线制）485接口 只用一片MAX488即能转换成功，其实是422通信方式，已经测试通过。 带有配套电源电路-232 be transferred directly into a full-duplex (4 wire system) 485 with only a MAX488 that is able to convert successfully, in fact, is a 422 means of communication have been teste