I have a SIM900 GSM Shield and I am using TinyGSM.
All I had to do to make it work was to change the GPRS jumper from SWSerial to Xduino (hardware).
Note that the jumper already connects GPRS-Rx to Arduino-Tx and GPRS-Tx with Arduino-Rx.
Code sample available at examples/GSM.ino.
| Shield | Arduino |
|---|---|
| VCC | 5V |
| GND | GND |
| D0 | Pin 14 (TX3) |
| D1 | Pin 15 (RX3) |
Below is a list of useful AT Commands.
| Command | Description |
|---|---|
| ATE1 | Enables command echo. |
| AT+CBAND? | Queries the current band configuration. |
| AT+CBAND=? | List all available band options. |
| AT+CBAND="X" | Sets the band configuration. |
| AT+COPS? | Queries the current operator. |
| AT+COPS=? | List all available operators. |
| AT+COPS=0 | Sets the current operator to automatic. |
| AT+COPS=1,0,"X" | Sets the current operator manually. |
| AT+CSQ | Queries the current signal strength (0-31). |
| AT+CREG? | Queries the current registration status. |
| AT+CENG=1 | Enables engineering mode. |
| AT+CMEE=2 | Increases error verbosity. |
| AT+CPIN? | Queries the simcard state. |
| AT+CFUN=0 | Sets chip functionality to minimal. |
| AT+CFUN=1 | Sets chip functionality to maximum. |
| AT+CFUN=1,1 | Sets chip functionality to maximum and restarts it. |
| A/ | Repeats the last command. |