Acura 2008 RL - Manual (Page 246)

If you are listening to XM Satellite
Radio, use the CH button to change
channels. Each time you press the
top (
) of the button, the system
goes to the next preset channel.
Press the bottom (
) to go back to
the previous preset channel.
To select a different channel of the
category you are listening to, press
and hold the top (
) or bottom ( )
of the CH button until you hear a
beep.
On U.S. models except Hawaiian
Remote Audio Controls
240