Lenovo M4400s notebook User Manual

Page 13

Using headphones or earphones

CAUTION:
Excessive sound pressure from earphones and headphones can cause hearing loss. Adjustment of
the equalizer to maximum increases the earphone and headphone output voltage and the sound
pressure level. Therefore, to protect your hearing, adjust the equalizer to an appropriate level.

Excessive use of headphones or earphones for a long period of time at high volume can be dangerous if the
output of the headphone or earphone connectors do not comply with specifications of EN 50332-2. The
headphone output connector of your computer complies with EN 50332-2 Sub clause 7. This specification
limits the computer’s maximum wide band true RMS output voltage to 150 mV. To help protect against
hearing loss, ensure that the headphones or earphones you use also comply with EN 50332-2 (Clause 7
limits) for a wide band characteristic voltage of 75 mV. Using headphones that do not comply with EN
50332-2 can be dangerous due to excessive sound pressure levels.

If your Lenovo computer came with headphones or earphones in the package, as a set, the combination of
the headphones or earphones and the computer already complies with the specifications of EN 50332-1.
If different headphones or earphones are used, ensure that they comply with EN 50332-1 (Clause 6.5
Limitation Values). Using headphones that do not comply with EN 50332-1 can be dangerous due to
excessive sound pressure levels.

Additional safety information

DANGER

Plastic bags can be dangerous. Keep plastic bags away from babies and children to avoid danger
of suffocation.

Save these instructions.