Interfacing Arduino with a Cellular GSM Modem

If you’re looking to make your Arduino talk with the outside world, you have lots of options.  A cellular modem can give you the most flexibility in terms of where and how you can send messages or transfer data.  Cell modems can be finicky and difficult to work with, but some are easier than others.

Although the Telit GM-862 has been superseded by other modules in Telit’s GSM lineup, it’s still relatively easy to find, easy to work with, and inexpensive.  Alexander Weber’s description of how to connect a GM-862 to the Arduino’s serial bus and his sample library code are largely applicable to many cell modems.  Most units still utilize some form the ancient Hayes AT command set, so the commands used in Alexander’s project can be adapted elsewhere with little modification.

4 thoughts on “Interfacing Arduino with a Cellular GSM Modem

  1. Pingback: Have your Arduino tweet, text, and post rambling Tumblr updates from anywhere using the official GSM/GPRS shield | EngBlaze

  2. GM862 monitor
    switching on
    done
    initializing modem …
    AT
    ->ok
    AT+IPR=19200
    ->ok
    AT+CMEE=2
    ->ok
    AT+CPIN=1234
    ->not ok: AT+CPIN=1234
    +CME ERROR: operation not allowed

    done
    version info …
    AT+GMI
    ->buf: AT+GMI
    Telit

    OK

    AT+GMM
    ->buf: AT+GMM
    GM862-GPS

    OK

    AT+GMR
    ->buf:
    AT+CSQ
    ->buf:
    done
    checking network …
    AT+CREG?
    ->buf:
    done

  3. I have made circuit as given in schematic where I am using Arduino Mega 2560 5v output as Vcc. Arduino itself is powered from usb. Status led flashes for few seconds and then turns off.

    • Hi Babar,

      I shortened your previous comment for brevity, hope you don’t mind. In the code you posted before, it looked like the circuit was working, but you were just having some issues with the AT commands. Is this issue with the Mega a separate problem?

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