This research investigates the recognition of limited letters in the noisy environment. This issue would be considered, when the driver listening to the music and driving the car simultaneously, which cause to reduce the concentration of driver on driving the car. The letters that driver would use are Next (next track), Previous (previous track), Louder (increase the volume), Lower (decrease the volume). In order to describe any frame, the LPCC constants and the sound energy with the first and second differentiations (39 characterizations in total) have been used.
