三菱FX2N 48MR，準備和計算機進行通訊。買了個232BD模塊。現(xiàn)在232BD和計算機上的串口接線，我看到資料上有不同說法，請問哪種是對的啊：
第一種說法：
                      232BD                                     計算機串口
                                            RD （2）-------------------------------- 5
                                            SG  （5）-------------------------------- 3
                                            SD （3）  -------------------------------- 2
第二種說法：
                     232BD                                       計算機串口
                   RD(2)      ---------------------------         2
                                      SD(3)     ----------------------------------3                                                
                                      ER(4)--------------------------------------4
                                      SG(5)--------------------------------------5
                                      DR(6)  -----------------------------------6                              

我怎么聯(lián)不上了，請大家指教