I was having great success with the GE865 evaluation board. With an AT&T SIM card pay as you go data plan I was sending SMS, email, and FTP. I put it down for 2 weeks, came back and my SIM card no longer connected. Before this 2 weeks the response to AT+CREG? was 0,1
But after 2 weeks, response to AT+CPIN? is OK and response to AT+CREG? is initially 0,2 (searching) and then 0,3 (denied).
I tried the SIM on my cell phone and it failed to connect. AT&T gave me a new SIM card. It worked on the phone, which by the way is an unlocked phone not associated with any provider. Put it into the GE865 evaluation board and response to AT+CPIN? is OK. Response to AT+CREG? starts as 0,2 then goes to 0,0. Put it back in my cell phone and it doesn’t connect. It looks like the evaluation board is killing my SIM card, but it still responds to AT commands.
I can’t imagine what is going on. All I did was solder headers to the through holes. The solder points all look fine. I was powering from the USB when the SIM died, previously I was powering from the USB and successfully sending data with the GE865.
Any thoughts on what is going on? I don’t want to keep killing SIM cards in this.
For any interested, I have subsequently tested serial communication from an arduino mega using the sparkfun logic level converter set to 2.5 V for the GE865, desoldered the USB connections on the evaluation board, and am successfully communicating between the arduino and the GE865. Now if I can just get the SIM card to not die.
I’m not sure if it’s related but you really shouldn’t be powering the thing from a USB port, especially if it’s a standard port. The USB port doesn’t source enough current to handle the large current spikes (close to 2 amps). I didn’t blow a SIM card but I was having inconsistent connection problems before I switched over to a wall wart. Just my two cents…
I saw the USB port power issue in the forum and the inconsistent connection problems it could cause. I am now powering from the wall but no luck with the SIM card. I’ll verify that the power supply can provide 2A, but given that the SIM doesn’t work in a regular cell phone anymore I don’t have much hope.
I didn’t see any concerns in the forum that powering from the USB could kill the sim card. I am not excited about trying out another SIM card just to test if powering from the wall doesn’t kill it. I suspect there is some other issue. I wonder if there is any way I can test the GE865 evaluation board further before sacrificing another SIM card.
Okay, I don’t understand the behavior of the SIM card. It now works in my cell phone. I’ll wait a day or two before trying it in my GE865 evaluation board to see if anyone has any ideas. I suspect the laptop power could have caused my original connection issues with the GE865 (for sure I will use a separate power supply next), but I can’t understand why it would then prevent the SIM Card from working in my cell phone for 24 hours. Unless AT&T was temporarily blocking it after its connection issues with a poorly powered GE865.
Does your SIM card use a PIN? It’s kind of strange that you get an OK response to AT+CPIN? because according to the data sheet that is not in the list of returned responses. Did you try checking the signal strength (AT+CSQ).
All is now working. Lesson learned, same as what the other posts have been saying, make sure you provide enough current for start up (2A!) and make sure the antenna is attached.
I still don’t understand why under-powering the GE865 would result in my SIM card not working in a regular phone for 24 hours. But all is working now so I’ll leave that question unanswered.