AT+CMGF=1 In text mode there are some additional parameters that can be set. Using the following command we can read the current values: AT+CSMP? The modem will reponse with a string like this: +CSMP: 1,169,0,0OK The first value is a combination of some option bits: bit 7 RP Reply path, not used in text mode bit 6 UDHI User Data Header Information bit 5 SRR Set this bit to request a delivery report bit 3,4 VPF Validity Period, set b4=1 if a VP value is present bit 2 RD Reject Duplicates, do not return a message ID when a message with the same destination and ID is still pending bit 0,1 MTI Message Type Indicatorb1=0 & b0=0 -> SMS-DELIVERb1=0 & b0=1 -> SMS-SUBMIT Bit 0 of the message is always set when sending messages (SMS-SUBMIT). So the first value should be 1 or higher. The second parameter sets the Validity Period of the message. This value is encoded as follows: 0 - 143 (VP + 1) x 5 minutes 144 - 167 12 Hours + ((VP-143) x 30 minutes) 168 - 196 (VP-166) x 1 day 197 - 255 (VP-192) x 1 week The third parameter contains the PID (Protocol Identifier). This parameter is only used for advanced messaging. The fourth parameter contains the DCS (Data Coding Scheme). This parameter is used to select the characterset/messagetype. When setting the DCS parameter to '0' standard 7 bit text is send. When setting this parameter to '16' the message is sent as a flash message. To send a message with a validity period of 1 day, the parameters have to be set like this: Bit 0 and 4 of the first field has to be set, so the first value will become 1 + 16 = 17. Send the following command to the modem to set this parameters: AT+CSMP=17,167,0,16 If the modem responds with "OK" ,the modem is ready to send (flash) text messages with a validity period of 1 day. Sending the message To send the SMS message, type the following command: AT+CMGS="+31638740161" Replace the above phone number with your own cell phone number. The modem will respond with: > You can now type the message text and send the message using the - key combination: Hello World ! After some seconds the modem will respond with the message ID of the message, indicating that the message was sent correctly: +CMGS: 62 The message will arrive on the mobile phone shortly.