SIM900 GPRS not responding to AT commands using Arduino

[lavared]

Hi,

I bought a seeedstudio SIM900 GRPS shield for arduino UNO and have been playing with it. I have been following all the instructions on how to operate it to send an SMS listed on their wiki page **broken link removed**.

When I send an SMS using Hardware UART (example code listed on wiki page) as listed on thier wiki page, my unit works perfectly and the SMS is send. However when I try to program the unit through a terminal program on PC (following Step 1 on wiki page using the example code listed there), the GPRS unit does not respond to any AT commands. I have tried different baud rates in the arduino sketch (9600,4800,19200) but the unit just doesn't respond to AT commands. I'm totally frustrated not knowing whatelse to try to make it work. For the Arduino, I'm using the latest NewSoftSerial (ver 10.c) as listed on the wiki page.

Kindly please help.

Lavan.

 

[ckshivaram]

use hyperterminal or tera term software and test it again.

 

[lavared]

use hyperterminal or tera term software and test it again.

Thanks Shivam,

yeah i did test it with tera term software but nothing happens when I send the commands.

 

[quark@mailinator.com]

Does your PC have a real COM port (RS232) or are you using one of those USB adapters ? The USB stuff is working correctly only half of the time and not always with all baudrates etc. Better get a real COM port (old PC or PCI board). Check if you need to activate some handshaking protocols in the drivers or so (RTS/CTS - see wikipedia about UART/RS232).