Arduino Nano and GSM 0308-71 Communication Problems

Using Arduino Networking, Protocols, and Devices
#1

Hi guys,

I am a novice arduino user. I'm trying to communicate with an Enfora GSM module via the serial pins on my arduino nano.

Arduino Pins - GSM Pins
3.3v VCC
GND GND
Rx RXD
Tx TXD
DTR and RTS pins pulled up through 100k Resistor.

I am trying to send a basic AT command to see if my arduino is communicating, but I keep receiving random numbers back.

Below is the code;

void setup()
{
Serial.begin(115200);
delay(5000);
Serial.println("AT");
delay(5000);
}
void loop(){
Serial.flush();
Serial.print(Serial.read());
delay(2000);
}

Can anyone help??

Thanks in advance.

#2

What version of the IDE are you using?

What do you think Serial.flush() is doing?

#3

serial.flush is there justs to make sure the serial data has finished transmitting.

Then, wouldn't it make sense to do that AFTER there is something to send?

but I keep receiving random numbers back.

It might be helpful to see those "random numbers".

#4

I couldn’t find documentation for your module (I couldn’t identify it) so this is not going to help, but the Nano has a 5V logic level, meaning that even if you power the module from the 3.3V output of the nano it will still receive 5V on the TXD pin, so I wonder whether your physical configuration is based on a reliable source.

The same for the baud rate of 115200, which looks pretty high for this kind of devices.

#5