Meet the future of Satellite IoT: Starnote for Iridium and Notecard for Skylo

Blues Developers
What’s New
Resources
Blog
Technical articles for developers
Newsletter
The monthly Blues developer newsletter
Terminal
Connect to a Notecard in your browser
Developer Certification
Get certified on wireless connectivity with Blues
Webinars
Listing of Blues technical webinars
Blues.comNotehub.io
Shop
Docs
Button IconHelp
Notehub StatusVisit our Forum
Button IconSign In
Docs Home
What’s New
Resources
Blog
Technical articles for developers
Newsletter
The monthly Blues developer newsletter
Terminal
Connect to a Notecard in your browser
Developer Certification
Get certified on wireless connectivity with Blues
Webinars
Listing of Blues technical webinars
Blues.comNotehub.io
Shop
Docs
Guides & Tutorials
Collecting Sensor Data
Routing Data to Cloud
Building Edge AI Applications
Best Practices for Production-Ready Projects
Twilio SMS Guide
Fleet Admin Guide
Using the Notehub API
Notecard Guides
Guide Listing
Asset Tracking with GPS
Attention Pin Guide
Connecting to a Wi-Fi Access Point
Debugging with the FTDI Debug Cable
Diagnosing Cellular Connectivity Issues
Diagnosing GPS Issues
Encrypting and Decrypting Data with the Notecard
Feather MCU Low Power Management
Minimizing Latency
Notecard Communication Without a Library
Recovering a Bricked Notecard
Remote Command and Control
Sending and Receiving Large Binary Objects
Serial-Over-I2C Protocol
Understanding Environment Variables
Understanding Notecard Penalty Boxes
Updating ESP32 Host Firmware
Using External SIM Cards
Using JSONata to Transform JSON
Using Notecard Trace Mode
homechevron_rightDocschevron_rightGuides & Tutorialschevron_rightNotecard Guideschevron_rightUsing Notecard Trace Mode

Using Notecard Trace Mode

All Notecards can be placed into trace mode. When enabled, a Notecard's trace mode generates a stream of messages that can help with debugging or understanding Notecard behavior.

You can utilize trace mode using:

  1. In-Browser Terminal
  2. Serial Terminal Apps
  3. _log Environment Variable
warning

Notecard's trace mode is available for debugging purposes only. The format of the output is not standardized and is subject to change at any time. If you need help interpreting a Notecard's trace output to debug an issue, reach out in our community forum or contact Blues support .

In-Browser Terminal

Complete the following steps to use trace mode via the In-Browser Terminal.

  1. Visit the In-Browser Terminal.

  2. Connect your Notecard to the terminal.

  3. Enable trace mode with the following request:

    {"req":"card.trace","mode":"on"}
  4. Perform actions that you want to debug. For example, to debug network connectivity issues you may wish to run a hub.sync request.

    {"req":"hub.sync"}
  5. Disable trace mode with the following request:

    {"req":"card.trace","mode":"off"}
  6. (Optional) Download the trace log using the Save History button in the top-left corner of the Terminal. This will download the contents of the Terminal history to a .log file. Saving history via Notecard In-Browser Terminal

Serial Terminal Apps

Complete the following steps to use trace mode via a serial terminal app.

  1. Connect a Notecard to your serial terminal app using one of the following serial port configurations.

    ConnectionSerial ConfigurationAbbreviated
    USBBaud Rate: 9600, 8 bit, no parity, 1 stop bit9600 8N1
    AUX RX/TXBaud Rate: 115200, 8 bit, no parity, 1 stop bit115200 8N1
    note

    Refer to our guides on using Tera Term and CoolTerm for more specific instructions on connecting to Notecard via those applications:

    • Configuring Tera Term to communicate with Notecard
    • Configuring CoolTerm to communicate with Notecard
  2. Enable trace mode with the following request:

    {"req":"card.trace","mode":"on"}
  3. Perform actions that you want to debug. For example, to debug network connectivity issues you may wish to run a hub.sync request.

    {"req":"hub.sync"}
  4. Disable trace mode with the following request:

    {"req":"card.trace","mode":"off"}

_log Environment Variable

You can remotely enable diagnostic logging at the device, fleet, or project level using the _log reserved environment variable. When enabled, this will save trace logs to the _log.qo Notefile on Notehub. Please note that the trace logs saved to Notehub using this method are far less verbose than the logs you can generate using the other methods outlined above.

warning

Saving and syncing logging data with Notehub will impact your cellular data allocation. To avoid unnecessary usage, enable this feature only when required and disable it immediately afterward.

  1. Set the _log environment variable using either the env.default API or the Notehub UI.

  2. When setting the variable, use one of the following values to specify the scope of the logging data to save:

    • gps (to save high-level GPS status information)
    • gpsmax (to save more verbose GPS logging)
    • power (to save power-usage snapshots from a connected Mojo)
    • modem (to save modem lifecycle and network state transitions)
    • all (to save more broad diagnostic data)
  3. Note that _log.qo Notes are generated only when a new Notehub session begins. If your Notecard is running in continuous mode, either set the _session_mins environment variable or set a duration value in your hub.set request. This allows you to define session length (in minutes) and ensure logs are created as expected.

  4. When finished gathering trace log data, be sure to delete these environment variables to silence logging and avoid unnecessary data usage.

Can we improve this page? Send us feedback
© 2025 Blues Inc.
© 2025 Blues Inc.
TermsPrivacy
Notecard Disconnected
Having trouble connecting?

Try changing your USB cable as some cables do not support transferring data. If that does not solve your problem, contact us at support@blues.com and we will get you set up with another tool to communicate with the Notecard.

Advanced Usage

The help command gives more info.

Connect a Notecard
Use USB to connect and start issuing requests from the browser.
Try Notecard Simulator
Experiment with the Notecard's API on a Simulator assigned to your free Notehub account.

Don't have an account? Sign up