Lenovo ThinkCentre 41X1308 Guide De Référence Rapide page 31

6. If you have audio devices, attach them using the following instructions.
For more information about speakers, see steps 7 and 8.
1 Audio line-in
2 Audio line-out
3 Microphone
4 Headphone
7. If you have powered speakers with an ac adapter, use the following
instructions.
a. Connect the cable that runs between the speakers, if necessary. On
some speakers, this cable is permanently attached.
b. Connect the ac adapter cable to the speaker.
c. Connect the speakers to the computer.
d. Connect the ac adapter to the ac power source.
8. If you have unpowered speakers with no ac adapter, use the following
instructions.
a. Connect the cable that runs between the speakers, if necessary. On
some speakers, this cable is permanently attached.
b. Connect the speakers to the computer.
9. Connect any additional devices that you have. Your computer might not
have all connectors that are shown.
This connector receives audio signals from an external audio
device, such as a stereo system.
This connector sends audio signals from the computer to external
devices, such as powered stereo speakers.
Use this connector to attach a microphone to your computer when
you want to record sound or if you use speech-recognition
software.
Use this connector to attach headphones to your computer when
you want to listen to music or other sounds without disturbing
anyone. This connector might be located on the front of the
computer.
Chapter 2. Setting up your computer
5