As it is now my sierra wirelss card is autodetected in /tmp/ppp0.3G to 460800 baud. I would like to have a higer speed since my service/card can handle 1.8Mbiut. how can i fix this so that its not reset on reboot?
The kernel modules that convert USB to serial are patched to recognize the model of modem UMTS/HSDPA and therefore they should automatically set the speed. In any case you could try a download to see if the connection is greater then 480Kbit/s.