What is the small number (1-4) in the upper left corner of the VVX-250 and in the upper left and right corners of the VVX-450?

he number indicates which column of speed dial sotfkeys are being displayed. There are four columns of speed dial softkeys which can be configured (numbered 1 through 4). Press the left arrow physical button (on the cursor wheel) to scroll through the four columns on the left.

The VVX-450 phone also has four columns on the right which you can scroll through using the right arrow physical button. Column 1 on the left side displays your line number and name.

On the VVX-250, you can have up to 15 speed dial buttons; on the VVX-450, you can have up to 35 speed dial buttons (using all four columns).