Troubleshooting; Segmenting And Reassembling Long Text Messages; Segmenting - Huawei MU609 Application Manual

HUAWEI MU609 HSPA LGA Module
Application Guide
AT+CMGD=1,4
OK

7.4.2 Troubleshooting

Scenario
Error information is returned
in response to one of the
previous commands.

7.5 Segmenting and Reassembling Long Text Messages

7.5.1 Segmenting

In PDU mode, text messages can be encoded using GSM 7-bit, 8-bit or UCS2. The
GSM 7-bit encoding scheme is used to encode common ASCII characters,
compressing every 8 characters into 7 characters. The 8-bit encoding scheme is
usually used to encode data such as pictures and ringtones. The UCS2 encoding
scheme is used to encode Unicode characters. According to the existing 3GPP
protocols, the size of the user data contained a PDU is 140 bytes. Therefore, the
maximum number of characters contained in a single message is 160, 140 and 70 for
the GSM 7-bit, 8-bit, and UCS2 encoding schemes respectively. If the number of
characters contained in a text message exceeds the maximum number, the message
will be segmented into several messages. An English letter, a Chinese character, or a
byte of data is considered as a character.
According to the existing 3GPP protocols, after a long text message is segmented,
the number of characters that each message segment can contain is as follows:



The number of available characters per segment is lower, because each segment
must contain segmentation information.
The storage space occupied by a character is as follows:

Issue 02 (2013-09-18)
GSM 7-bit encoding: 153 characters
8-bit encoding: 134 characters
UCS2 encoding: 67 characters
GSM 7-bit encoding: 7 bits
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Copyright © Huawei Technologies Co., Ltd.
Text Message Application Scenarios
Delete all the messages in the current
storage.
Possible Error
Information
ERROR
+CMS ERROR: 500
Solution
In Text mode, run
AT+CMGL=4 (number), or in
PDU mode, run
AT+CMGL="ALL" (string),
and ERROR is returned.
During SIM card initialization,
run AT+CMGL or AT+CMGD
to read or delete a message,
and an error is returned.
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