INTERFACE GSM MODEM WITH 8051

Interfacing of GSM modem with microcontroller for sending and reading SMS is quite Simple

You need following signals:

1. Connect RTS Signal of GSM modem with CTS signal
2. connect RxD of the modem with RxD of 8051
3. Connect TxD of modem interface with TxD of 8051
4. GND of modem connectes with GND of 8051

You can send SMS through GSM modem through commands sent by 8051 to the modem using AT commands

regards
m.yasir

Hello M. Yasir,
I am doing d simialar project which involves sending SMS and reading received SMS , now i can send sms. for that purpose I have stored AT Commands in a lookup table , but now I am not able to read the received sms.

Plz help me , ITS URGENT....

I Have verified reception of an sms in hypertreminal, are we supposed to directly recive d same nw msg acknolegment in microcontrollers sbuf ??

i did a small program just to verify if RI gets set on SMS /CALL or not , I just blinked a LED if RI is set and d code works fine, LED glows as long as i am calling d modem.
but when i tried to read d content of sbuf it just show '0A'....

Where is d problem ??
Where I am going wrong ??
Please Help me..............

2. connect RxD of the modem with RxD of 8051
3. Connect TxD of modem interface with TxD of 8051

m.yasir

correct this..
RxD of Modem goes to txd of 8051 and txd of modem goes to rxd of 8051.

@CHIMU,

I suggest you a better way. try polling method, read location 1 of message and read whatever is sent by modem. if new message is there.. you will get string in format
"\r\n+CMGS: ....."
if no sms is there then
"\r\nOK\r\n"

and after you read that sms simply delete it. so next time when u read that location you will get "\r\nOK\r\n" which means no new sms

Hi all
Im going to do my project :receiving and sending SMS with 8051.I search the schematic .but somewhere i dont understand as i highlighted:.http://s1022.photobucket.com/albums/af344/trial32/?action=view&current=sim_reader_tivald.gif
anyody can hepl me >how it was.

@trial: which modem are you using?

The modem i am using this was uploadd in this forum :
i saw someone use <printf("....") instruction to write some command as printf("at+cmgr=1"). now i am use Keilc compiler .and keilc havent suported to make "printf(".....").What compiler are u using?
thanks for your help.

trial, are you sure you know what you're doing??

coz the above circuit is for SIM interface not a modem. Visit market once or search in google for modems to get more clear view.

Sorry.I was wrong with the view .I will try any more.nowaday i understand some .
thanks .