I am trying to connect to my cellular modem on Linux. I connect it through USB and the device appears as /dev/ttyUSB0. Using minicom, I set the port and baud rate then connect to the device. However, when I connect I get a weird output.
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I turned on echo in minicom (crtl+a e) and when I try to enter a newline, this output just repeats. I also cannot get a response when issuing AT Commands.

What does this output mean? Any other suggestions on what I can test?

Thank you.


I would like you to give me more information to help you, here I leave what I need:

  • When you connect the USB modem to the PC, open the console and type: dmesg | grep tty. Could you let me know the answer? This is to verify where the modem was connected, I currently have one and it connects as /dev/ttyACM0

  • Are you sure you're using the right speed (baudios)? This problem seems typical of a poorly chosen speed.

  • I check that when using the Minicom instead of entering the program and then configure parameters it is preferable to access it directly with the parameters already offered, for example: minicom -D /dev/ttyACM0 -b 9600 Being the -D for "device" and -b for "speed" in (baudios)

  • I tired the suggestion you have made still had no luck. I doubled checked the datasheet and found the USB is used for firmware updates, not AT commands. Should have checked prior. Thank you for the help! – Nick Yameen Jan 5 '18 at 16:45
  • Anyway, the modem that I use is the Keyestudio SIM900 GSM-GPRS shield for Arduino, if I can help you with this (I love those things) just ask me for help :-) Greetings! – k.Cyborg Jan 5 '18 at 17:06

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