I uploaded the code to arduino when the sim990 plugged on it,, now the sim900 not works, even just for check the IMEI , it doesn't works, the result: no modem answer,,
I have read on the article, when upload the code, better to unplug the sim900,,
how to fix it? please help
I use arduino uno & ICOMSAT V1.1 sim900 as the GSM shield
I would. Separate the two modules. Then establish that the Arduino is not damaged by loading in a couple of basic scripts like "blink" or something.
Then power up the GSM separately with a valid SIM card (no PIN number) in of course and see if it logs on to a network. Watch the flashing LEDs.
Can you phone it and get a dialling tone??? If you can then it is probably not damaged.
If the GSM module doesn't light up at all then there is a more serious issue.
Try again to join them up.