A6 gprs/gsm

Hardware Arduino GSM Shield
3

I have just started using this device & here are my findings so far

  1. PWR_KEY should be connected to VCC - this can be regarded as chip select
  2. RESET must pulled low for a few millisecs. You can't do this via an Arduino GPIO as it takes too much current. I use a 2222A transistor to do the job.
  3. Initial baud rate is 115200 which means that talking via SoftwareSerial is very flaky.
  4. I tried changing baud rate to 9600 but found that in fact nothing happens. The modem reports OK to the change but carries on using 115200.

Nonetheless, do the following to get some sign of life.

  1. Connect PWR_KEY to 5V of Arduino
  2. Connect UART_RXD to pin 3 of Arduino
  3. Connect UART_TXD to pin 2 of Arduino
  4. Connect any GND from modem to Arduino GND
  5. Power up modem from a USB charger that supplies at least 2 amps
  6. Run the attached sketch. At first you will not see anything happening.
  7. Take a wire and momentarily connect RESET to any GND (on modem or Arduino)
  8. After a few seconds data will start appearing in the terminal window

/------------------ simple sketch
#include <SoftwareSerial.h>
SoftwareSerial mySerial(2,3);

void setup()
{
Serial.begin(115200);
mySerial.begin(115200);
};

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