hello,
i use ppp to connect to internet a dell latitude d500 laptop using a vodafone huawei e220 modem.
time to time, the connection is lost,and if i try again ppp-go i have this output(not all the time,sometime work ok) :
if i reboot it's working fine.how do i solved without rebooting ?(google did not help)

I have never used ppp, but did you try open the file /etc/ppp/options to see configuration relates to /dev/ttyUSB0?

/dev/ttyUSB0 is the name of the device, usually included in a single line in the configuration file. When the file exists, pppd interprets the line as the device to use. If the file does not exist, pppd prints that confusing error about the device name being an unrecognized option.

This has happened to me with a Huawei E220 too. Sometimes, an error happens and the device disappears. A few of those times, the device appears again as ttyUSB1 or ttyUSB2. My recommendation is to use a symbolic link instead. For example, I use /dev/modem and make it point to ttyUSB0 or whatever ttyUSB* device is first found, using a script, before calling pppd.

thank you rg3, i will try it !