Module sim900A initialize testing...

Hi all,

I follow the instructions to testing sim900A, but ONLY can receive message/call from another cellphones, NOT call/send from sim900 to any cellphones. Anybody have experiences on this case?

I cannot even sent AT command to test operation status; receive message is okay now; here my logfile. Thank you in advance.


+CFUN: 1


Call Ready

+CMT: "+8498???????","Xi l","14/09/28,22:50:44+28" Trying... AT


I can't see any code.

dannable: I can't see any code.

I remember to get into command mode on one of my SIM 900 I had to press caps and send a capital letter. After that the at commands worked fine.

Worth a try.

Thanks you for your replies, Dannable & Casemid.

Dannable: I just connected sim900A and PC and using Terminal software to send AT command, not develop any code yet.

And, I found that I cannot send string "CR" character by Terminal; I make a test by convert to Hexa, sending "AT\n" by "41-54-D" instead, It can respond OK now.

So, do you know how can I send CR+LF after each commands, in case no need convert?


I guess you mean the arduibo terninal? If so, There is an option for line ending. You can select none, carriage return, new line, or /CR + /n.