What are transpose and tuning? How do you change key or pitch?

Transpose allows you to change the pitch of the keyboard into another key. This eliminates awkward fingerings in difficult keys, and lets the keyboard be adjusted for singers, and wind and other instruments. Tuning adjusts in much smaller steps, so you can get even closer to what the singer sounds like.

On the PX-100 digital piano, this information can be found on page E-19 of the Users Guide. It is also known as "Changing Piano Key" or "Changing Pitch".