I use a device that is connected to my Linux (Fedora21) PC via usb-com serial adapter. When device is connected and /dev/ttyACM0 is created in system something sending a series of modem AT-command for it initialization.

Since my device is not modem, I would like to disable that behavior.

So the question is, how to disable such probing?


The something that probes your port is most likely ModemManager, which is part of the NetworkManager suite.

If you have no (classic or wwan) modem installed in your system, the easiest thing to do is to remove ModemManager from your system. If you do have such a modem, then you can add a udev rule to signal to ModemManager that this device is not a modem and that it shouldn't even probe it:

ATTRS{idVendor}=="1234", ATTRS{idProduct}=="5678", ENV{ID_MM_DEVICE_IGNORE}="1"

where 1234 is the vendor id of your device, and 5678 the product id (you can find these with lsusb)

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