how to read the received message/number from microcontroller

[Chandan]

Dear Sir, 

               We, a group of four are involved in a GSM-microcontroller interfaced project in which we are trying to receive acknowledgement from the specific number. ie,  

             I command the GSM to dial a particular number through 89c51 and after some time I need an acknowledgement from the same number either via call  or SMS. I need the phone number for valid verification. In this regard can you please help us how to extract the number through AT commands.                                          

[AJISH ALFRED]

The GSM modem can be configured like the following to response immediate when a SMS is received, the SMS’s details are immediately sent serially

AT+CMGF=1	To format SMS as a TEXT message
AT+CNMI=1,2,0,0,0	Set how the modem will response when a SMS is received

When a new SMS is received by the GSM modem serially send the following data

+CMT :  “+91xxxxxxxxxx” , , “04/08/30,23:20:00+40”
This the text SMS message sent to the modem

If you take a close look, it can be found that the 8th character is the starting of the mobile number after a character ‘+’ has been received for the first time.

So just wait till the ‘+’ is received for the first time, then count the next 7 characters received, start storing from the 8 th charater onwards into an array till the 20 th character and you have the mobile number in that array, like +91xxxxxxxxxx

[raju]

sir,

how to read sms using gsm & 8051 & display on 16×2 lcd.

[nilesh]

Hi,

 

       You need to write some code .I hope you successfully interface UART and modem.When you receive the msg on GSM  collect the data in the buffer and at the end of the msg you will get +CMT. check +CMT and set the flag. I am going to write some rough logic.

 

if((MSSG[3] == '+')&& (MSSG[2] == 'C')&& (MSSG[1] == 'M')&& (MSSG[0] == 'T'))

{  

sms_rcv = 1;

} 

 

 

if(sms_rcv)

{

sms_rcv = 0;

delayMs(1000);

parse_msg();       // here check the buffer in which you received the data.and send it on LCD

del_sms();

}

[Anonymous]

Sorry… did not get your point….

can you please explain this bit clearly…

[Anonymous]

Enable the uart interrupt.once msg recived you will get symbol < .collect the msg in uart receive buffer.

[Author]

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