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Cannot access the message from GSM Mdem to Microcontoller

Hi, I can send the command "AT+CMGR=1" To GSM modem, but after that i cannot access the message from it. The modem is "Iwow" and microcontroller is 89c52. I have used Tx, Rx and ground pin of RS232. whether it is necessary to use RTS and CTS pins for this modem? When i send the command "AT+CMGR=1" to GSM modem, a pulse will be coming at TI pin of microcontroller. meanwhile there is no pulse at RI pin, indicating no message has been retrieved from GSM modem. But if i connect it to Hyperterminal i can read the message.

Please find a solution to this problem..

Parents
  • I have used MAX232 as a transceiver( To convert to TTL LEVEL). Programming is done using C code. When i send the AT command like, AT+CMGR=1 a pulse wil be observed at TI pin of Microcontoller(checked using digital probe). But later, pulse is not observed at RI pin.since there is no indication of data at RI pin, the program will halt at the statement- while(RI==0);

    wether GSM modem is not accepting that format?( GSM Modem used is of 'IWOW').

Reply
  • I have used MAX232 as a transceiver( To convert to TTL LEVEL). Programming is done using C code. When i send the AT command like, AT+CMGR=1 a pulse wil be observed at TI pin of Microcontoller(checked using digital probe). But later, pulse is not observed at RI pin.since there is no indication of data at RI pin, the program will halt at the statement- while(RI==0);

    wether GSM modem is not accepting that format?( GSM Modem used is of 'IWOW').

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