I am trying to connect a IoT node to a IBM IoT server via MQTT/GSM. I am using a Sim800L GSM module, and a serial USB device to send the commands to module from my computer. Later on, I will use the commands on Arduino to register my device. I'm sending following command to GSM Module:


And I get the following output


But for connecting my device to BlueMix, I need to submit username and password. There isn't any documentation that I find on doing that, so i tried that:



And after a few seconds after sending that:


So I think that this is not a valid way to submitting user and password. But I couldn't find any documentation about authentication on MQTT with GSM.

  • Isn't the "AT+CIPSEND" command suppose to be similar to an HTTP GET request? You send how many bytes are going to be sent, then the next line is your http request. So for Username/Password, you would send an 'Auth' header with a base64 encoded "username:password" string as the data. Not sure how that is done on the ESP32. AT+CIPSEND=64\nGET /page... "exploreembedded.com/wiki/Setting_up_GPRS_with_SIM800L"
    – JD Allen
    Commented May 24, 2018 at 3:25
  • techtutorialsx.com/2018/01/03/…
    – JD Allen
    Commented May 24, 2018 at 3:34
  • @JDAllen I've found a library to end this pain anyway, thanks.
    – codemonkey
    Commented May 24, 2018 at 14:51
  • Hello Sir i have the same Project like THis with all ( SIm800L, IBM Bluemix, node red , all like you ) Can you Help Me please , i want to publish to node red from Sim800L Commented May 13, 2019 at 13:00
  • Hi @NadjibJipou, unfortunately i can't remember about it since it is one year ago. The library i gave the link should work for you i guess.
    – codemonkey
    Commented May 13, 2019 at 18:03

1 Answer 1


I've found this library useful to solve issues with authentication. If you encountered same issues on GSM modules with Arduino, it may help you as well:



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