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<a href="index.html">Home</a
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<h3>User Data Header</h3>
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User Data header was added to the SMS format specification to add new features.
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Originally SMS was made to send single small binary files or text messages, with a maximum of 140 bytes or 160 7-bit characters.
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But now mobile devices need to distinguish between different files, for example ringtones, operator logos and wap-push messages.