Appendix C - DB9-M Analog audio input pinout
Pin
Signal
1
Left + (Audio 1)
2
Left - (Audio 1)
3
Ground
4
Right - (Audio 1)
5
Right + (Audio 1)
6
Left + (Audio 2)
7
Left - (Audio 2)
8
Right - (Audio 2)
9
Right + (Audio 2)