Samsung ML-2151N-XBH - Manual (Page 165)

U SING Y OUR P RINTER WITH A M ACINTOSH A.10
Paper Source
If you installed the optional
Tray2, check this box to
activate Tray2.
Select the corresponding paper source.
If Auto Select is set, the printer
automatically selects the print material
from the paper tray, according to the
following order: Multi-Purpose Tray, Tray1
and the optional Tray2.