How do states use OBD II for emission inspections?

Many states connect a computer directly to a vehicle's OBD II system. The inspector can then read "faults." In some states, this type of inspection has replaced the tailpipe emission test.
See also:
Replacing batteries in the headphones
The headphones use two AAA batteries.
It is advisable to have extra batteries on hand
during long trips.
Battery cover and retaining screw
1. Unscrew the retaining screw and remove
the batter ...
Warning symbols on the battery
NOTE
A used battery should be disposed of in an
environmentally responsible manner. Consult
your Volvo retailer or take the battery to
a recycling station. ...
USB
USB connector in glove compartment
If you connect an iPod
, MP3 player or a USB
flash drive to the optional USB connector, this
device can be controlled using the vehicle's
audio controls ...
