I'm using the SIM900 GPRS/GSM shield from ICOMSat (v1.1), connected to my Arduino Mega.
I'm having trouble connecting it properly. The shield fits on to the Mega with the antenna on the USB port side. I connected it so that the connectors on the left hand side (antenna on top edge when you look at it from above) are connected to the Arduino board's 3.3V, 5V, GND and Vin pins.
I can start the module up, and it registers on the network (NET LED is on for 64ms, off for 3000ms).
Connecting the UART is what troubles me. I understand how the multiplexer works and how you can use it to select pins for your software serial library. I need to know how to connect the module if I wanted to use on of the hardware UARTs on the Arduino board.
I have searched through the forum and data sheets but I just can't seem to get it right.
On the right hand side there are 3 rows of pins, one row for RX, one for TX and one for the pins to the arduino. The pins in the RX row and TX row are all connected.
Remove all connectors on these pins.
Connect by seperate cable RX to arduino mega pin 18, TX to mega pin 17. This makes the connections for Serial1, same use as Serial.
i am in one trouble and need quick solution.
when i am connecting my GSM sim900 with arduino then in serial monitor it shows the error and it shows
'Starting modem test...ERROR, no modem answer.
Checking IMEI...Error: Could not get IMEI'
i have connected Tx pin of GSM with Tx1 pin(pin no.18) of arduino and Rx pin of GSM with Rx1 pin (pin no. 19). please give suggestions as fast as possible. Also guide me for the connections if i have done the wrong connection.
