GSM shield with SIM900 is not logging in

Projects Networking, Protocols, and Devices
1

Hello Adruino friends,

ich would like to hook up a small project. In need this for resetting my firewall at home because it's doing strange stuff from time to time.
I followed this instruction (attached, but in german, sorry) to hook up the GSM shield to see if I get this running. Unfortunately it's not doing well.

Configuration:

  • UNO replica board: mikrocontroller board with ATmega328P, ATmega16U2, compatible with Arduino UNO R3
  • GSM shield SIM 900
  • both boards have their own power supply
  • gnd connection between them
  • changed the jumper on the UNO for software serial
  • software serial connection on Pins 7 & 8 on UNO -> crossed connection to the GSM shield
  • used this code to send SMS
  • changed TX und RX ports to 7 and 8 in GSM.ccp
//De-comment this two lines below if you have the
//second version og GSM GPRS Shield
//#define _GSM_TXPIN_ 2
//#define _GSM_RXPIN_ 3
#define _GSM_TXPIN_ 7
#define _GSM_RXPIN_ 8

Execution:

  1. power both up
  2. hit power button on GSM shield

Error:
The GSM shield can't log into the net:
The net LED indikcates this.
On the serial monitor in the Adruino IDE I get this:

GSM Shield testing.
ATT: OK
RIC: ⸮⸮⸮⸮
ATT: OK
RIC: ⸮⸮⸮⸮
ATT: OK
RIC: ⸮⸮⸮⸮
ATT: OK
RIC: ⸮⸮⸮⸮
ATT: OK
RIC: ⸮⸮⸮⸮

I could not find any final solution on my search. Do you have any ideas?

I appreciate any kind of ideas or crtitic.

Thanks Karl

SIM900.pdf (861 KB)