SMS – AT Commands, Text Mode, PDU Mode, SMS PDU Converter

This SMS tutorial will cover the following topics,

SMS Message Format – Text Vs PDU

All modem devices support 2 types of SMS message format – Text & PDU (Protocol Data Unit). Depending on what SMS message forma is set, the AT command format to send and read SMS messages will vary. Text format is straight forward to use. PDU format gives more control over the content of the message such as encoding type (other language character set), how long the message is valid, protocol identifier (fax, voice etc),
reply path etc.

With AT Command Tester, you can read and set the SMS Message format type.


//Get the SMS Message format
AT+CMGF?

+CMGF: 0

OK
SMS message for is configured for PDU mode

^RSSI:8

//Set SMS for Text format
AT+CMGF=1

OK
//Set SMS for PDU Format
AT+CMGF=0

OK
SMS message for is configured for Text mode
AT+CMGF?

+CMGF: 1

OK
SMS message for is configured for Text mode

Using the “Show Text Format” and “Show PDU Format”, users can check AT command formatted
message even without connecting the device.

Destination Number – 8588780098
Message – SMS Message sent from AT Command Tester

Text Mode Formatted Message
AT+CMGS=8588780098
SMS Message sent from AT Command Tester.

PDU Mode Formatted Message
Validity Period Format (VPF) -> 2
User Data Header Indication (UDHI) ->0
Status Report Request (SRR) -> 0
Message ID (MR) ->0
Data Coding Scheme (DCS) -> 7-bit
Validity Period (VP) ->170
Message Type (MTI) ->1
Reject Duplicates (RD) ->0
Reply Path (RP) ->0
SMS Service Center -> 2160130300F4
Message Content ->D3E614D42CCFE7E17319342FBBE920B3FCDD0605A9A0E1BBDD0EBBC9206A794E2FCB5D
PDU ->07912160130300F411000A8158888700890000aa28D3E614D42CCFE7E17319342FBBE920B3FCDD0605A9A0E
1BBDD0EBBC9206A794E2FCB5D
AT+CMGS=55
07912160130300F411000A8158888700890000aa28D3E614D42CCFE7E17319342FBBE920B3FCDD0605A9A0E
1BBDD0EBBC9206A794E2FCB5D

Send SMS in Text Mode

With Online AT Command Tester tool, you can send SMS messages in Text or PDU format. The tool will automatically detect what format (Text or PDU) is currently set on the device and will send appropriate AT commands to send the SMS message.


Checking registration status...

AT+CREG?

+CREG: 2,1, 8E, CE87

OK
The device is registered in home network.

Checking SMS Mode…

AT+CMGF?

+CMGF: 1

OK
SMS message for is configured for Text mode
Device is configured for Text mode for SMS.

AT+CMGS=”8588780098″

> SMS Message sent from AT Command Tester.

+CMGS: 22

OK

Send SMS in PDU Mode

Now let us send message in PDU mode. First change the SMS message format using the AT+CMGF command.

AT+CMGF=0

OK
Checking registration status…

AT+CREG?

+CREG: 2,1, 8E, CE73

OK
The device is registered in home network.

Checking SMS Mode…

AT+CMGF?

+CMGF: 0

OK
SMS message for is configured for PDU mode
Checking SMS Mode…

AT+CMGS=48
> 07912160130300F411000A8158888700890000aa28D3E614D42CCFE7E17319342FBBE920B3FCDD0605A9A0E
1BBDD0EBBC9206A794E2FCB5D

+CMGS: 23

OK

PDU Message format

The PDU format gives more control over configuring the SMS message. In AT Command Tester, the PDU settings can be configured as shown below,

The format of the mobile-originated SMS message (SMS-SUBMIT) is as follows,

PDU data Conversion
Destination Number – 8588780098
Message – SMS Message sent from AT Command Tester
SMSC Address – 12063130004
Encoding – 7-bit

PDU
07912160130300F411000A8158888700890000aa27D3E614D42CCEE7E17319342FBBE920B3FCDD0605A9A0E1
BBDD0EBBC9206A794E2FCB01

Field Value Description
SCA(Service Center Address) 07912160130300F4 07- length
91 – Address type
2160130300F4 – Service center address
PDU-TYPE 11 Reply Path (RP) ->0
User Data Header Indication (UDHI) ->0
Status Report Request (SRR) -> 0
Validity Period Format (VPF) -> 2
Reject Duplicates (RD) ->0
Message Type (MTI) ->1
MR (Message ID) 00
DA (Destination Address) 0A815888870089 0A – Lenght of the address
81 – Address Type
5888870089 – Destination phone number
PID (Protocol ID) 00
DCS (Data Coding Scheme) 00 00 – Default 7-bit encoding
VP(Validity Period ) AA
UDL (User Data Length) 27 0×27 – 39 characters of user data
UD (User Data) D3E614D42CCFE7E17319342FBBE920B3FCDD0605A9A0E1BBDD0EBBC9206A794E2FCB01 User data with 7-bit encoding
SMS Message sent from AT Command Tester

 

Read SMS Messages

You read all the SMS messages stored on the device.



AT+CMGL="ALL"

+CMGL: 0,”REC READ”,”1511″,,”14/01/31,17:56:01-32″
Welcome to T-Mobile! Dial #BAL# to check your balances. Your T-Mobile number is 1858xxxxxx
+CMGL: 1,”REC READ”,”1511″,,”14/03/14,13:31:57-28″

OK

Keywords: Module SM AT Commands, M2M SM AT Commands, GPRS SM AT Commands, 3G SM AT Commands, SM AT Commands through AT commands,