How ttyUSB* created on my 3G modem problem

Hi

I would like to ask if someone knows the explaination of the /dev/ttyUSB*. I had a internet connection 3G usb dongle modem and need to restart before it detected the mobile broadband in the network manager. Before i reinstalled the lucyd lynxs i never meet this problem. But after i reinstalled the lucyd lynx i need to put the usb modem first before starting my system.. but if i plug my usb modem in a running state the network manager doesn't detect the mobile network therefore a remedy is plug first and restart.

One thing i notice if i had a working usb modem is i had a /dev/ttyUSB1-4 but if i plug it later and dont have a working usb modem.. i dont have the /dev/ttyUSB*.

I dont know if i this is the cause or the services that doesn't start if a plug the usb in running state..

Hope someone knows and understand my problem.