I recently bought a 3G wireless card to use with my laptop, a ZTE, model MF622.
Since the first time I tried linux, also the first time I encountered this kind of problems with my usb ADSL modem, and this being an usb modem also, I knew I was going to have troubles.
At first I tried USB ModeSwitch which has experimental support for ZTE’s MF620 model with no luck. I then followed the instructions on the site to snoop the usb comunication under M$ Win to get the messages being sent to the device so I could mimic that under linux. Still, no luck.
I then tried to code a python script which used the libusb so that I could make the device switch to the modem configuration. Still, no luck.
I spent a lot of time on this subject and then one time I removed the usb_storage module while hal was waiting for the device to settle down and guess what!? After a few seconds, the device changed itself to the modem configuration. All I needed now was to automate this procedure.