When connecting a Huawei E173 mobile internet stick (and probably a lot of others as I have seen, but I have several of the E173) the first thing that comes up is the driver CD. When using from a terminal (in Linux for example) this can be annoying but the usb_modeswitch will do the switch and the modem will come up. Except when there are more than one sticks connected. Then you will need some luck (could not find out why this is happening) to make the switch on the latest stick.
Fortunately enough there is a solution to skip all the hassle and make the modem jump right into modem mode!
To disable the CD-ROM, the SD card reader the need of usb_modeswitch and jump straight to modem mode on Huawei E173 mobile internet stick you need to send the following AT command: AT^U2DIAG=0
Note: you can use any program that can communicate with a modem via serial interface (minicom for example or hyperterminal (for Windows guys)). You might also still need to do a modeswitch one time to be able to enter this command.
The AT^U2DIAG sets what component/function is available on the stick to the user. (See the previous link for more info.) You can also check the current setting entering AT^U2DIAG? (yes, the questionmark is the part of the command).
I wrote this post for the reason I could not find these info easily enough from time to time… I had to try a few google searches to find the answer, maybe I am not the only one who had this problem and I might have used better keywords.