LTE Cat M1/NB-IoT Shield Hookup Guide

Contributors: jimblom
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If you are running into trouble with your LTE shield, here are some troubleshooting tips and guides that may help you figure out what might be going on:

Troubleshooting Resources

Troubleshooting Steps

  1. To begin troubleshooting your shield, make sure you are following the hookup guide exactly.

    Why? The assembly instructions and example codes have been tested and are known to work. It will also be easier to narrow down the problem because any deviation from the hookup guide may be causing the issue(s).
  2. Use the SparkFun Troubleshooting Tips to do an initial check of any issues you may have missed. These include, but are not limited to:
    • Double checking your power. Use a multimeter to it is getting the right voltage or enough current?
    • Double check your soldering. Are there any cold joints?
    • Double checking your wiring or connections and use a multimeter to test all connections.
    • Do you have the right board selected in the Arduino IDE? Are you using the right COM port?
    • Double check the baud rate for the Serial Monitor.
    • Have you tried a different computer, USB cable, or microcontroller board?
    • etc.

  3. Verify that your Hologram SIM card is activated. If you have reached the free 1MB data limit, you will need to wait for the next month/billing cycle or add a payment method for your account.

  4. Check your area of coverage. Hologram has a wide variety of contract carriers, but they do not have coverage everywhere. If you or your project are in an area with low or minimal cellular coverage, you may run into issues because of that.

  5. As part of our QC process, all shields should have been tested with a known working Hologram SIM card. However, here are a few tests and sketches you can run to verify the functionality of the board. (*These tests assume that you have already addressed the previous items 1-4 and you are testing the shield in the US. If you live outside of the US, you may need to modify the library for your carrier information.)

    1. Without the LTE shield, upload Blink to make sure your microcontroller is working.
    2. With the LTE shield on the RedBoard:
      1. Check the hardware connections for continuity, switch positions, make sure the SIM card is inserted fully, and check that there is power going to the LTE module. (i.e. Uploading code, while the switch is in the SERIAL - [HARD] position will cause issues.)

      2. Don't forget to use the push buttons to power/reset the LTE module.

      3. Run the Serial_Passthrough example code to verify the microcontroller can talk to the LTE shield.

      4. Run the Ping_SIM_card.ino ( Click Link) to verify that you are reading the SIM card. You may need to run this sketch a few times, there were a small number of instances that is gave false negatives. However, a failure here could indicate that your SIM card isn't seated properly or there is a connection issue.

      5. Run the 00_Register_Operator example sketch from the library. This will be the first sketch that tests the functionality of the LTE shield.
        • You may need to adjust the mobile network operator (MNO) setting on line 45.
        • You may also need to set the APN on line 51 .

      6. Run the Network_Info example sketch from the library. This sketch initializes the LTE module and checks that it can connect to a mobile network.
        • You may need to adjust the mobile network operator (MNO) setting on line 83.

Frequently Asked Questions

Are the Hologram eUICC SIM Card's Special Features Supported with the LTE Cat M1/NB-IoT Shield?

The Hologram enhanced eUICC SIM card [ e.g. CEL-17117 ] will work with SparkFun LTE CAT M1/NB-IoT Shield - SARA-R4 [ e.g. CEL-14997 ] but the special eUICC features will not be operable with the shield at this current time.

If you need further assistance with these key features please visit the Hologram support forum: