Ricoh M281 Series Service Manual page 928

Bit Switches - 2
3 Binding direction for Duplex printing
0: Left binding
1: Top binding
4-7 Not used
* This setting can be used for the client machine which has no FCU.
D255/D256 FAX OPTION
0: Sets the binding for the left edge of
the stack.
1: Sets the binding for the top of the
stack.
Do not change the settings.
94 SM