Hello guys. I attached a Mini SIM to my SIM900 GSM Shield. I had already connected the Antenna to the shield and attached the shield to my Arduino Uno directly (Without jumper wires).
TECHNICAL DATA:
- GSM SIM900 shield is connected directly to an Arduino Uno
- Antenna is attached to the shield
- I am using my USB connection as a power supply (also need to see output on the Serial)
- The sim card is not locked with a PIN. I can insert it into cellphones without typing in a code.
- *I do possess the PINs & PUKs codes that came with the SIM if necessary.
Basically, here are my errors with each of the next GSM examples:
- TestGPRS, initializing GSM gsmAccess(true); to see debug messages. This is the output when a PIN code is not inserted, it's stuck here:
Connecting GSM network...AT%13%
0 9>AT%13%%13%%10%OK%13%%10%
AT+CGREG?%13%
9 40>AT+CGREG?%13%%13%%10%+CGREG: 0,4%13%%10%%13%%10%OK%13%%10%
AT+CGREG?%13%
The output when either PIN1 or PIN2 codes are inserted to .begin():
Connecting GSM network...AT%13%
0 9>AT%13%%13%%10%OK%13%%10%
AT+CPIN=1111%13%
9 31>AT+CPIN=1111%13%%13%%10%ERROR%13%%10%
ERROR
- The "Change PIN" example says this:
PIN & PUK locked. Use PIN2/PUK2 in a mobile phone.
However, as mentioned, after getting this message I put the SIM in a cellphone and the cellphone just made use of it without the need of a code, so this is probably incorrect.
- The simple "SendSMS" example is stuck with this message forever:
SMS Messages Sender
If I insert either PIN1/PIN2 codes, it will refuse connection (saying "Not Connected")
I looked it up on the internet, unfortunately there weren't many discussions and none of the suggested solutions worked for me so far.
Also, apologies for including so much information, just wanted to avoid suggestions that were already tried 
Thanks in advance for any expert who knows the way around this problem.