Demonstrating How to Use the +CMGR AT Command to Read SMS Text
Messages from a Message Storage Area (SMS PDU Mode)
let's see a more detailed example that demonstrates how to use the
+CMGR AT command to read SMS text messages from a message storage
area when SMS PDU mode is used, and how the +CMGR AT command should
be used together with other AT commands.
the GSM/GPRS Modem or Mobile Phone to Operate in SMS PDU Mode
instruct the GSM/GPRS modem or mobile phone to operate in SMS PDU
mode by entering the command line "AT+CMGF=0" in a terminal
program (for example, HyperTerminal in Microsoft Windows). Below
shows the response returned from Nokia 6021 to HyperTerminal after
the execution of the command line "AT+CMGF=0":
final result code OK indicates the +CMGF AT command was executed
successfully. If the final result code ERROR is returned, it is
likely that the GSM/GPRS modem or mobile phone does not support SMS
PDU mode. To check whether the GSM/GPRS modem or mobile phone
supports SMS PDU mode, enter the command line "AT+CMGF=?"
in the terminal program. Here is the response returned from Nokia
6021 to HyperTerminal:
values in the parentheses indicate the modes that the GSM/GPRS modem
or mobile phone can operate in. The value 0 represents SMS PDU mode
and the value 1 represents SMS text mode. From the above response, we
know that Nokia 6021 can operate in either SMS PDU mode or SMS text
mode. See the section titled "Selecting
the Operating Mode (AT+CMGF)" of this SMS tutorial if you
want to learn further details about the +CMGF AT command.
the Message Storage Area to Read SMS Text Messages from
use the AT command +CPMS (command name in text: Preferred Message
Storage) to select the message storage area to read SMS text messages
from. For example, to instruct the GSM/GPRS modem or mobile phone to
use the message storage area in the SIM card for the AT command
+CMGR, enter the command line 'AT+CPMS="SM"' in the
terminal program. Then press the Enter key on the keyboard and you
should see something similar to this:
information about the +CPMS AT command is available in the "Preferred
Message Storage (AT+CPMS)" section of this SMS tutorial.
you can now use the +CMGR AT command to read a text message from the
message storage area. Let's say you want to read the SMS text message
at index 1. You should enter the following command line in a terminal
press the Enter key on the keyboard and the GSM/GPRS modem or mobile
phone will execute the command line "AT+CMGR=1". If it
reads the text message successfully, the result returned should look
something like this:
is a brief description of the various field values in the information
value of the first field, 0, indicates the status of the SMS message
is "received unread", i.e. it is an SMS text message
received from the SMSC and it has not been read.
value of the second field should be a string that contains the text
associated to the sender's phone number "+85291234567" in
the phonebook. In this example, this field is empty. One possible
reason is that the GSM/GPRS modem or mobile phone (for example,
Nokia 6021 and many other Nokia products) does not support this
value of the third field, 62, indicates the TPDU encoded in the
hexadecimal sequence consists of 62 octets.
details of the SMS text message are encoded in the hexadecimal
sequence. Examples include the sender's phone number, the body of
the SMS text message, the time and date at which the SMS text
message arrived at the SMS center, etc. We have discussed how to
decode the hexadecimal sequence in the section titled "Some
Explanation about the Decoding of the SMSC_number_and_TPDU Field
Value of the +CMGR AT Command" of this SMS tutorial. Thus,
we will not talk about it again here.
final result code OK indicates the SMS text message was read from the
message storage area successfully. If the execution of the +CMGR AT
command fails, the GSM/GPRS modem or mobile phone will return either
the final result code ERROR or +CMS ERROR.
using the +CMGR AT command to read the SMS text message, its status
was changed from "received unread" to "received read".
So, if the command line "AT+CMGR=1" is executed again, you
will see a slightly different result (note the part highlighted in
SMS text message retrieved above is an incoming text message. Note
that if the SMS text message retrieved is an outgoing text message,
the data contained in the hexadecimal sequence will have a different
format and it should be decoded according to the section "Some
Explanation about the Coding of the SMSC_number_and_TPDU Parameter
Value of the +CMGS AT Command" of this SMS tutorial.
there is no message located at index 3 of the message storage area.
If you specify the index 3 to the +CMGR AT command, the GSM/GPRS
modem or mobile phone will return +CMS error 321 (which means the
index is invalid), like this:
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