Invalid or no response from the device

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This topic contains 25 replies, has 2 voices, and was last updated by  Mojako 5 years, 11 months ago.

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  • #5092 Reply

    Admin
    Keymaster

    Jerry,
    The IMEI is read from the module, so I dont think the SIM card would matter for that.
    Did you have the software serial selected(jumpers) as shown in the image?(see link)
    http://www.seeedstudio.com/wiki/File:Power_to_SIM900.jpg

    • This reply was modified 6 years ago by  Admin.
    #5104 Reply

    Jerry

    My jumpers were not like the ones in the picture. I thought the shield came by default in software serial. I changed my jumpers and still have the same errors with modem test and AT command tester

    Starting modem test…ERROR, no modem answer.
    Checking IMEI…Error: Could not get IMEI

    #5106 Reply

    Admin
    Keymaster

    What arduino board are you using?

    #5107 Reply

    Jerry

    arduino uno

    #5108 Reply

    Jerry

    R3, the most recent one.

    #5109 Reply

    Admin
    Keymaster

    What is the status of LEDs – Power-on indicator, Status indicator and Net indicator?

    LED Status Function
    Power-on indicator(Green) Off Power of GPRS Shield is off
    On Power of GPRS Shield is on
    Status Indicator(Red) Off Power off
    On Power on
    Net indicator(Green) Off SIM900 is not working
    64ms On/800ms Off SIM900 does not find the network
    64ms On/3000ms Off SIM900 finds the network
    64ms On/300ms Off GPRS communication

    #5110 Reply

    Jerry

    I have the Power LED(green) on
    I have the Status Indicator(red) on
    I have the Net Indicator(green) blinking at every 300 ms

    #5112 Reply

    Jerry

    its actually more like every 800ms

    #5113 Reply

    Jerry

    I think the software serial should be the one on the left.
    http://www.seeedstudio.com/wiki/File:Sofeware_Serial.jpg
    On the wiki page, the location of the jumpers change after the boards are stacked…
    So far what I’ve done is loaded this code onto my arduino (without gprs)

    #include <SoftwareSerial.h>

    SoftwareSerial mySerial = SoftwareSerial(2,3);

    void setup()
    {
    Serial.begin(9600);
    Serial.println(‘Begin’);
    mySerial.begin(19200);

    }

    void loop()
    {
    if (mySerial.available())
    Serial.write(mySerial.read());
    if (Serial.available())
    mySerial.write(Serial.read());

    }

    Then i connect my gprs and attempt to use your AT Tester and it gives me the above mentioned errors. Is there anything im missing? is there a reason why we’re using pins 2 & 3 for tx and rx? shouldnt we be using
    D7: Used as RX of software serial port
    D8: Used as TX of software serial port

    #5114 Reply

    Admin
    Keymaster

    The baud rates should match..

    Serial.begin(19200); h/w serial port
    Serial.println(‘Begin’);
    mySerial.begin(19200); s/w serial port

    The SIM900 module should be configured for the same baud and you should choose teh same rate in the AT Command Tester as well…

    If SIM900 is not configured for above baud rate, then you should try different rate in the in the shield and reload..

    #5993 Reply

    Mojako

    My Problem same like Jerry, I use Adruino Mega 2560 and still can not use my GPRS Shiled V 2.0.
    My Jumper set to HardwareSerial and also upload TestModem Sketch. and still massage “ERROR, no Modem answer”. Do I missed something? please help

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