Sorry, the Model is MF627 and not MF726.
I seriously apologise for this blunder.

I take it that you didn't have the problem in windows. I use the u760
3g modem. Because the device has a memory device built in to install a
driver for windows, I must eject the memory device before the system
recognizes the modem. I have set up the network connection to auto
connect so should the reception be weak it will reconnect when the
connection fails.

I found the information on my modem on the Sprint network site, you may
look up your modem and determine it is supported with Linux on the
manufactures website.

The other option is to use a WiFi port, I have a friend that uses such a
device and then the OS is not important.

Yes, you are right. My modem never got disconnected in windows. Can you please
elaborate upon using wifi ports with mobile broadband. Because, I am a total
dumb in computers.

WiFi is not the same as 3G but I guess you know that.

WiFi is almost automatic with my machine so there is not much to tell.
The launch bar(top bar) has the available connections listed, and
selecting one of them is all I have to do. The 3G connection is under
the mobile broadband heading. If it fails to show there then you likely
have not ejected the memory device that should show up on your desktop
with the name of your phone service. You can change the setting to
automaticly connect under admainistration>Preferrences>network settings.
Just select the connect automatically button and that should do it.