怎样把三芯XLR连接器焊上电缆线呢？（内芯装置）

The international application standard IEC 60 268-12 defines wiring of XLR connectors. The following is a brief description of the 3 pole version.

Pin1 --> Xternal of cable (shield/ground)
Pin2 --> Live (“Hot” /+ polarity)
Pin3 --> Return (“Cold” /- polarity)