Sony PSP-1001 Instruction Manual page 108

Parental Control Level
Some UMD™ software have a preset parental control level based on the
content. You can set the parental control level on the system to restrict the
playback of a UMD™ with a level that is higher than that set on the system.
Parental Control Level
The parental control level of the system can be either turned off or set to one of
11 different levels.
Off
11-1
The default setting for the menu item is "9".
The combination of the parental control levels of both the PSP™ system and
the UMD™ determine whether a UMD™ can be viewed or not. The
combination of the two levels is displayed in the table on page 109.
Example: If the parental control level of the system is set to "9", a UMD™ with
a level from "1" to "9" can be played on the system.
108 Security Settings
Turns off parental control
Sets the level of content to be restricted. A setting of "1" is the most
restrictive; "11" is the least restrictive.