Ricoh Aficio MP 1600 General Settings Manual page 256

Registering Addresses and Users for Facsimile/Scanner Functions
F
Press the {OK} key.
G
Press [Details].
H
Select [Auth. Protect] using {U} or {T}, and then press the {OK} key.
I
Select [Destination Protect] using {U} or {T}, and then press the {OK} key.
7
J
Enter a protection code using the number keys, and then press the {OK}
key.
K
Select [Folder Protect] using {U} or {T}, and then press the {OK} key.
248