Docomo LYNX SH-10B Instruction Manual page 126

Using unknown source's application
<Unknown sources>
You can allow installation of application received via mail or site other than
Android Market.
1
In the main menu, [Settings]/[Applications]
2
[Unknown sources]
: Each time you select, the setting is enabled/disabled.
Applications you download from the sites may be of unknown origin. To
protect your FOMA terminal and personal data, download only
applications from trusted sources such as Android Market, etc.
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