1、PC/AT 机上的串行口是 9 针公插座，引脚定义为：Pin Name Dir Description1 CD Carrier Detect2 RXD Receive Data3 TXD Transmit Data4 DTR Data Terminal Ready5 GND System Ground6 DSR Data Set Ready7 RTS Request to Send8 CTS Clear to Send9 RI Ring IndicatorPC/XT 机上的串行口是 25 针公插座，引脚定义为：Pin Name Dir Description1 SHIELD - Shield
2、Ground2 TXD Transmit Data3 RXD Receive Data4 RTS Request to Send5 CTS Clear to Send6 DSR Data Set Ready7 GND - System Ground8 CD Carrier Detect9 n/c - 10 n/c - 11 n/c - 12 n/c - 13 n/c - 14 n/c - 15 n/c - 16 n/c - 17 n/c - 18 n/c - 19 n/c - 20 DTR Data Terminal Ready21 n/c - 22 RI Ring Indicator23 n/c - 24 n/c - 25 n/c -
