Sony PCG-VX88 - Manual (Page 75)

To connect external speakers
1. Verify that your speakers are designed for computer use.
2. Turn down the volume of the speakers.
3. Locate the Headphone jack, and plug the speaker cable (not supplied) into this jack.
See the manual that came with your speakers for more information on its installation and use.
Connecting Speakers to the Headphone Jack
Page 75