Lexmark T650n Service Manual page 255

250-sheet/550-sheet tray assembly
Rear media tray guide
Media size sensing
The media size set for the media tray assembly is set by positioning the right media guide, unlocking the slider
lock, and sliding the rear paper guide. The rear paper guide triggers the movement of the auto size sensing
finger, which then sets the switches of the controller card board. The combination of ON/OFF position of the
three switches provides information of the media sizes to the engine.
Note: Media size sensing through ON/OFF switch combination
Lockable back restraint
Auto size finger actuator
Media size
Unknown
A4
Legal
B5
A5
Executive
Letter
Custom
Media end guide
SW 1 SW 2
OFF OFF
OFF OFF
OFF ON
OFF ON
ON OFF
ON OFF
ON ON
ON ON
4062-XXX
SW 3
OFF
ON
OFF
ON
OFF
ON
OFF
ON
Diagnostic aids
3-53