Start wvdial on boot from crontab

I'm trying to get work crontab, I'm editing crontab with sudo crontab -e. After that I add the line @reboot wvdial at the end of file, theoretically, every boot the computer connect with wvdial but it doesn't work, why? Where I'm wrong? I'm trying also with @reboot /usr/bin/wvdial but no chance to get this work. How can I set up my crontab file to run wvdial successfully at startup? When capturing the output from wvdial, I see this: --> WvDial: Internet dialer version 1.61 --> Cannot open /dev/ttyUSB1: No such file or directory