SIM900a Modem IMEI 0, Help with TX RX Pins

[fwd82]

Hello
I have Simcom SIM900a GSM (SIM900 (SIM900A) Mini DEV Board v3.9.2) and I am interfacing it with Arduino UNO.
I have no idea how to connect SIM900a to Arduino UNO.

What I did now is:

I connect the following Pin from above Image to:

5 to: GND (Digital GND near Pin 13)
6 to: 5V of Arduio

2 to: GND of Arduino near 5V
3 to: Digital Pin 0 of Arduino (RX)
4 to: Digital Pin 1 of Arduino (TX)

1 to: (No idea)
From Picture option 7, 8, 9 are not connected to anything.

Can you please guide me am I doing right?
I am getting hard time to find out what is TX and RX in my SIM900a module as it is not written there.

My SIM900a looks like this:

SIM900A V4.0 GSM GPRS Kit Wireless Extension Modul

http://upsats.com/Content/Product/img/Product/Large/SIM900V4-G36-37C.jpg (Schematics given)
SIM900 (SIM900A) Mini DEV Board - ElectroDragon

When I upload sketch of:
Example > GSM > TestModem:

I got this output from Serial Monitor:
Starting modem test...ERROR, no modem answer.
Checking IMEI...Modem's IMEI: 0
Reseting Modem... Modem is functioning properly: IMEI: 0

[hugo007]

Hi
If you look to the datasheet (http://www.datasheetcafe.com/sim900a-datasheet-pdf/) you can find that the RX/TX pins are pin10/pin9 in the modem, so it should be trivial to follow the trace and find out what pin is in the header connector.

5 to: GND (Digital GND near Pin 13)
You may need to swap the pins RX to TX of arduino and vice-versa.
6 to: 5V of Arduio

Pay attention that SIM900 need more current than your arduino 5V rail can supply.YOu should get an external 5V power supply that can supply a current about 2 A during modem current peaks.