Dell Venue 8 (7840, Early 2015) - Manual (Page 17)

Setting Up Your Tablet | 17
Using Headphones
You can connect a headset, headphones, microphone, or other audio
equipment to the headset port of your tablet.
WARNING: Listening to loud music for an extended period of
time can lead to hearing loss.
1 Connect headphones to the headset port (3.5 mm) on the tablet.
2 Insert the earbuds in your ears, or wear the over‑ear headphones
over your head, and then adjust the volume to a comfortable
level.
NOTE: When you connect an audio device to the 3.5 mm
headset port, the integrated speakers on your tablet are muted
automatically.
CAUTION: To prevent damaging your headphones when
disconnecting it from the tablet, pull the connector and not the
cable.