Samsung SDP-850DX Software User's Manual page 18

Digital function is not supported from this product.( It is maintained in non-activated condition
at all times.) PRESET(Psav, Pexe) button inter-operates with the number button(1~8). (Refer
to Samsung Digital Presenter User's Manual)
Psav(Preset Save)/Pexe(Preset Execution) :
Allow to save the customized user setting values or to activate the preset user setting. After
pressing Psav / Pexe button press number keys from 1 through 4 within 5 seconds.
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