Multi-Tech Systems GPRS (MTMMC-G) User Manual

Chapter 9 – Short Messages Commands  

Multi-Tech Systems, Inc. Wireless GSM/GPRS AT Commands (Document Number S000293I) 

64 

 
Command Syntax: AT+CPMS=<mem1>,[<mem2>],[<mem3>] continued 

AT+CPMS= “SM” 
Note: Selecting SM for reading, 
writing and storing has not 
changed 

+CPMS: “4,10,4,99,4,99 
OK 
 

AT+CPMS? +CPMS: 

“SM”,4,10,”ME”,4,99,”ME”,4,99 

OK 
Note: Read SMS from SIM. Write and store SMS from/to flash 

 

 

 

Description: 

The message formats supported are text mode and PDU mode.   

In PDU mode, a complete SMS Message including all header information is given as a binary string (in 
hexadecimal format). Therefore, only the following set of characters is allowed: 

  

{‘0’,’1’,’2’,’3’,’4’,’5’,’6’,’7’,’8’,’9’, ‘A’, ‘B’,’C’,’D’,’E’,’F’}. Each pair of characters is 

converted to a byte (e.g., ‘41’ is converted to the ASCII character ‘A’, whose ASCII 
code is 0x41 or 65).  

 

In Text mode, all commands and responses are in ASCII characters.  

 

The format selected is stored in EEPROM by the +CSAS command. 

Values: 

0 PDU 

mode 

1 Text 

mode 

 

The <pdu> message is composed of the SC address (00 means no SC address given, use default 
SC address, read with +CSCA command) and the TPDU message.  

 

In this example, the length of 

bytes of the TPDU buffer is 14, coded according to GSM Technical 

Specification 03.40.  

 

In this case, the TPDU is: 0x01 0x03 0x06 0x91 0x21 0x43 0x65 0x00 0x00 0x04 0xC9 0xE9 0x34 
0x0B, which is GSM 03.40: 

 <fo> 

0x01 (SMS-SUBMIT, no validity period) 

(TP-MR)  

0x03 (Message Reference) 

  

0x06 0x91 0x21 0x43 0x65 (destination address +123456) 

(TP-PID)  

0x00 (Protocol Identifier) 

(TP-DCS)  

0x00 (Data Coding Scheme: 7 bits alphabet) 

(TP-UDL)   0x04 (User Data Length, 4 characters of text) 

 

0xC9 0xE9 0x34 0x0B (User Data: ISSY) 

 

TPDU in hexadecimal format must be converted into two ASCII characters; e.g., an byte with 
hexadecimal value 0x2A is presented to the ME as two characters ‘2’ (ASCII 50) and ‘A’ (ASCII 65). 

Syntax:   

Command Syntax: AT+CMGF<mode> 

AT+CMGF ? 
 
Note: Current message format 

+CMGF: 1 
OK 
Note: Text mode 

AT+CMGF=? 
 
Note: Possible message format 

+CMGF: (0,1) 
OK 
Note: Text or PDU modes are available 

AT+CMGF=0 
Note: Set PDU mode 

OK 
Note: PDU mode valid 

AT+CMGS=14<CR> 
0001030691214365000004C9E9340B 
Note: Send complete MSG in PDU mode, no 
SC address 

+CMGS: 4 
OK 
Note: MSG correctly sent, <mr> is returned