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Using SMS Messaging
SMS messages are sent to an SMS Center (SMSC), the SMSC uses a
store-and-forward technique to try to reach its destination. If a message can not be
delivered, it is stored for later retransmission. The maximum size of the message
depends on the encoding method used. For instance, the most common GSM 7-bit
alphabet allows for a 160 character message.
Your modem can send and receive SMS messages in both text and PDU (Protocol Data
Units) mode. This chapter will explain the differences between the two methods and
show you how to send and receive a text message in both formats.
Important:
If you plan to use SMS messaging, confirm that your data plan supports it. SMS
is not always included with M2M data plans, and often there is an extra cost to support SMS
messaging.
Text vs PDU Modes
Your modem is capable of sending SMS messages in both text and PDU modes. Text
mode is simpler to use, bit it does not allow you to use different encoding methods for
your message. PDU mode supports different encoding methods, giving you greater
control over your message. PDU mode lets you do a lot more including sending EMS
messages, graphic messages, flash SMS messages, and messages in different
languages.
PDU mode is more widely implemented by modem and mobile phone manufacturers
than text mode and is more flexible, so it’s usually the best format for sending SMS
messages.
Since Text mode is easier to use, we’ll show you how to use that first, if you don’t want
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