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<concept id="GUID-0BC9A9A1-DB99-5095-8390-E1C1B04D0080" xml:lang="en"><title>Introduction</title><prolog><metadata><keywords/></metadata></prolog><conbody>
<p>When you send an SMS message all of the characters in the message are encoded
as 7-bit GSM code or Unicode Character Set-2 (UCS-2). The message is then
sent in one or more Protocol Data Units (PDU). A PDU contains information
about the control, address and data to deliver an SMS message. </p>
<p>The 7-bit encoding cannot represent all characters. UCS-2 includes all
of the characters within the Basic Multilingual Plane, but it reduces the
number of characters in one PDU from 160 to 70. Users are often charged by
the PDU. A message encoded using UCS-2 can be more expensive than the one
encoded using 7-bit GSM. There are four types of SMS encodings to encode an
SMS message: </p>
<ul>
<li id="GUID-B548C03F-BCCF-58EC-8043-844372B5A91E"><p><xref href="GUID-FE94596E-B5BB-51FE-BE38-069840323915.dita#GUID-FE94596E-B5BB-51FE-BE38-069840323915/GUID-F7D1E6C8-9605-57FA-9788-AF7FC72BD94C">7-bit GSM encoding</xref>  </p> </li>
<li id="GUID-C486071F-F184-5DD8-BA4A-51444548DD38"><p><xref href="GUID-FE94596E-B5BB-51FE-BE38-069840323915.dita#GUID-FE94596E-B5BB-51FE-BE38-069840323915/GUID-918FF2E3-B9F4-5C61-8DBA-F9143DB16460">Lossy 7-bit encoding</xref>  </p> </li>
<li id="GUID-EE33620C-7D69-5BDE-8CBB-ADE2D0CE6BAD"><p><xref href="GUID-FE94596E-B5BB-51FE-BE38-069840323915.dita#GUID-FE94596E-B5BB-51FE-BE38-069840323915/GUID-D2F0E6BE-932E-545D-A0C8-39017E3D67B4">16-bit Unicode encoding</xref>  </p> </li>
<li id="GUID-1B9705DF-2187-5F43-9615-C43D58417A3C"><p><xref href="GUID-FE94596E-B5BB-51FE-BE38-069840323915.dita#GUID-FE94596E-B5BB-51FE-BE38-069840323915/GUID-93B3DDF2-8EB1-5853-9DFD-3ABF42ADCB40">National language encoding.</xref>  </p> </li>
</ul>
<p>The following character converters are used in the SMS encodings: </p>
<ul>
<li id="GUID-822C740E-9A27-5D82-BD68-B7094113B535"><p><xref href="GUID-0CD18555-07EB-545D-9D47-D69A6BE6D2C8.dita">Standard
SMS Converter</xref>  </p> </li>
<li id="GUID-E0633334-73B7-5A72-835B-080E78655703"><p><xref href="GUID-B1254526-3C72-59E7-88C0-667FC051379F.dita">Extended
SMS Converter</xref>  </p> </li>
<li id="GUID-87BA0ABD-13E7-58B8-8335-7BCE105AD68C"><p><xref href="GUID-738FADA9-E26F-53F1-A6D6-2E82019DDA1F.dita">Turkish
National Language Support</xref>. </p> </li>
<li><p><xref href="GUID-C524C3E8-D151-5AB2-8791-1342C297FFBB.dita">Portuguese National
Language Support</xref></p></li>
<li><p><xref href="GUID-4A9053C2-80ED-5FB7-B07D-E1DC5D965213.dita">Spanish National
Language Support</xref></p></li>
</ul>
</conbody></concept>