Hi every body I has config dongle with imei code and i get an error 'failed to get valid response from /dev/ttyUSB1' my /etc/asterisk/dongle.conf file is [dongle0] ;audio=/dev/ttyUSB1 ; tty port for audio connection; no default value ;data=/dev/ttyUSB2 ; tty port for AT commands; no default value imei=867919014541497 Please help me to slove this issue Thanks so much