I am using Arduino board interface with SIM800A module. I cannot upload my program to the board. Please help me.
Please show the connection schematic ...
Probably the RX, TX terminals are reversed.
These errors point out that the Arduino is not answering the calls.
Thank you for your reply.
My sim800A module have 3 pins namely Tx,Rx & gnd.
I connect common ground and Tx is connect to pin 9 & Rx is connect to pin 10.
My code is below .
gsm.println(“AT+CMGS=”+919626678809"\r"); //replace x by your number
If you disconnect the SIM800A module from the Arduino, are you then able to upload?