The code is tested with SIM900A and Arduino UNO. Connect the Tx and Rx pins of arduino pins to Rx and Tx pins of GSM Modem. Note: The uart pins should be cross connected, ie. Om muruga urumi mellam. GSM Tx –> Arduino Rx and GSM Rx –> Arduino Tx. Make the ground common between Arduino and GSM modem. TTL pins can be seen just behind the 9 pin DB9 connector.
Active2 years, 4 months ago
I have a problem. I bought a SIM900 board, but I can not connect there with the Arduino. To send AT commands on the serial the SIM900 doesn't respond, but the LED indicating that the network is on. I've tried to change the baud rate of 9600 to 19200 in the firmware of the Arduino, but it still fails. I think I'm having a problem with the connections of the SIM900, since this board strikes me as obscure (could not find the schematic on the Internet)
The board I have is identical to this:
I'm 90% sure that I am connecting to the wrong pins. But I tried to reverse the jumpers and even some soldered pins on UART.
Greenonline
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1 Answer
I'll tell you what worked for me, because I didn't find the schematics of this board. But your board may work differently, so it is always good to check the datasheet and the schematic (if you have one). Rachel portman albums.
Power
Be sure to use an external 5V source that can supply up to 2A without dipping significantly.
CodeConnectionTesting..
Open the serial monitor Arduino, set the baud rate in 19200 in 'Both NL & CR'. If not work, set to 'Carriage Return'. Type 'AT' and wait for an OK.
HelpGsm Modem Sms Messages
If you need help, these links were useful to me:
dda
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Gsm Module Sim900 SpecificationNot the answer you're looking for? Browse other questions tagged gsm or ask your own question.Comments are closed.
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