Joke Collection Website - Public benefit messages - I use the serial port to send instructions to sim900a. I sent AT before, and its response was ok, but I never found the internet, so texting failed. Later, even at didn't respond.

I use the serial port to send instructions to sim900a. I sent AT before, and its response was ok, but I never found the internet, so texting failed. Later, even at didn't respond.

I use SIM900. There should be little difference. After the power is turned on, there are two indicator lights, one is on for a long time, and the other is flashing once every 6S, indicating that the network has been searched. If it flashes once every 1, network search, and data transmission is in progress every 3S. Also, make sure that your baud rate is set correctly. If the baud rate is set to AT+IPR=***, you must use the same baud rate to communicate with the serial port.