Comments: RETIRED - MG2639 Cellular Shield Hookup Guide


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  • -------------------- Tech Support Tips/Troubleshooting/Common Issues --------------------

    Super Friend's Button

    For a tutorial of the SparkFun Super Friend's Button that was used in the demo video [ ], try looking at Shawn's tutorial here => [ ].

    Serial Communication Issues

    Certain Arduino IDE versions can be incompatible. I heard from another support representative that the software serial baud rate had some compatibility issues with Arduino IDE v1.6.9 and above. This will create issues when trying to communicate with the MG2639 cellular shield. Try using Arduino v.1.6.3 like the tutorial, 1.6.5, or v1.6.6. Otherwise, you would need to go into a library and manually change the baud rate.

    You can also try to change the MG2639's baud rate and using a modified AltSoftSerial by checking out this post in StackExchange for Arduino [ ].

    Arduino IDE Compatibility?

    I had a case where the MG2639 cellular shield was not working on an Arduino Uno and the Arduino IDE v1.8.1. They had this error:

    Unable to communicate with shield. Looping

    By downgrading to Arduino IDE v1.6.5, they were able to get the shield working with the example code. It's possible that the latest Arduino IDE has some bugs causing it not to work with the MG2639 shield and Arduino Uno.


    Looking at the user manual [pg 10 -, it appears that the MG2639_V3 uses the GSM850/EGSM900/DCS1800/PCS1900 band with a maximum theoretical downlink of 85.6kbps . Checking against the speed of the different generations [ ], it looks like the MG2639 is using 2G:

    GSM (Global System for Mobile Communications) 2G -- 9.6Kbps
    GPRS (General packet radio services) 2.5G -- 35Kbps to 171kbps
    EDGE (Enhanced Data rates for GSM Evolution) 2.75G -- 120Kbps to 384Kbps
    UMTS (Universal Mobile Telecommunications System) 3G -- 384Kbps to 2Mbps
    HSPA (software upgrade to UMTS, theoretical 42Mbps) 3.5G -- 600Kbps to 10Mbps, averages 1-3Mbps
    WiMAX/LTE "4G" (theoretical 100Mbps) -- 3Mbps to 10Mbps average, 20Mbps+ peak download speeds.

    • Member #879159 / about 7 years ago * / 1

      bboyho, would you mind explaining how/where to manually change the baudrate? I'm worried I'll break everything...

      (I've looked through the main .h and .cpp files in src but not sure whether to unwrap autobaud() or delete and replace entirely. What would you recommend?)

  • Member #233066 / about 8 years ago / 1

    When I try the simple example "MG2639_GetInfo" I get this warning during building "WARNING: Category '' in library SparkFun MG2639 CellShield is not valid. Setting to 'Uncategorized'"

    Then, when I upload the sketch and start the program by sending some chars on the serial line, the MG2639 RSSI led blink quickly during 2-3 sec then stay OFF and I get the following message "Unable to communicate with shield. Looping".

    Im using using the last Arduino IDE version, with a RedBoard, external 9V power, standard SMA antenna for the GSM. Exactly like in the hookup guide.

    Does anyone have an idea?

  • Member #812832 / about 8 years ago / 1

    Has anybody gotten the GPS to work?

  • Member #650916 / about 8 years ago / 1

    Would the minimum connection requirements to the Arduino board, when not stacking, be those listed above: VIN, Ground, Cell UART TX, Cell UART RX? This is assuming manual BOOT using the button on the shield.

  • Member #400734 / about 9 years ago / 1

    For Jimbo: Could the MG2639 Cellular Shield be configured to be a wifi hub? How many devices could be connected? I would like to use it to connect a few electric imp boards accessing the network at different times.

  • Parizival / about 9 years ago / 1

    In the supplying power section, should it be cellular shield instead of lipo shield in the caption? "LiPo batteries are a perfect power supply for the LiPo shield"

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