when i try to find signal strength of my modem using AT+CSQ, the usb device is locked by the network manager. To find the signal strength with AT+CSQ i have to first disable network connection using #nmcli nm wwan off to unlock the device inode /dev/ttyUSBX. Is there any nmcli option to get signal strength or any other option? EDIT The gdbus object for NetworkManager don't have any method like getSignalStrength. Network manager is locking device file preventing to use AT commands. nm-applet was able to display signal strength in system tray. so there should be a way to get signal strength form network manager! nmcli is command line counter part of nm-applet. Can i get signal strength using nmcli? nothing about signal strength is mentioned in its man pages.