Canon imageCLASS MF6540 Basic Operation Manual page 41

U [Tone] key
Press to switch from rotary pulse to tone dialing.
V [2 on 1] key
Press to set 2 on 1 copying.
W [Frame Erase] key
Press to set frame erase for copying.
X [Collate] key
Press to set collate copies.
Y Additional Functions key
Press to select or cancel the modes in
Additional Functions.
Z [2-Sided] key
Press to set two-sided copying or faxing.
1-6
a [Enlarge/Reduce] key
Press to enlarge or reduce copy ratio.
b [Density] key
Press to adjust the density for copy or
documents you send.
c [Image Quality] key
Press to select image quality for copy or fax.
d [Paper Select] key
Press to select a paper source (paper cassette or
multi-purpose tray).