SIM card problems

Forum 2005-2010 (read only) Hardware Interfacing
1

Hi!

I have a problems with sagem HILO shield and a SIM card.

The problem is that the SIM auto-off at 7 seconds after turning on the module. Allways arround 7 second. After that I must push again the ON button.

I test the module without microcontroler (Arduino microcontroler) and conected to Hyperterminal.

within the first seconds I CAN send AT commands and I GET response. about seven second the connection get down.

I tried whit other SIMs and I got NO PROBLEMS. Only whit these SIM card. I tried this card in a movil phone and it run well.

Someone can help me??

TAHNKS and...sorry about my english.

2

Ok I go on researching and I have new datas.

The others SIMS disconnect too, but only after put in the PIN code. Before enter the pin code I CAN use AT commands without problems (without limit of time).

What can be happening?

3

All my tests with industrial cellular modems use to be done with no pin SIMs. Just erase it with any mobile and then try again. Maybe this helps!

4

I think you are going to find this is a power supply problem. I had the exact same problem when I was prototyping a SimCom GSM module.

How are you powering the device? You're power supply must be able to supply at least 2 amps so it can't be powered through USB. What's happening is the modem is trying to register to the network and you're power supply is dropping out causing it to shut down.