SLT ZTE ZXDSL 852 Modem Install,Configure on Ubuntu.....
1st Step : Download UbuDsl installation Package
This Guide is for Following Modem(In Picture)

2nd Step : Installing
Double click on the downloaded package

Afterwords following window will pop-up. Just click the Install Package button on that window.



Click next. Then you will have to type in your login name & your
login password. Choose your country & your ISP name. Don't check or
uncheck other options. Default settings will work fine.


Then the applet will ask you to insert & select your installation
volume. In that case just put in your Linux installation CD (in my case
Kubuntu 8.10 CD) & click OK.


Finally UbuDsl will finish configuring your modem & will attempt to
establish connection. It is recommended to reboot the computer after
that.

If everything went fine, after rebboting the computer UbuDsl will
establish the connection immedialely & you now can surf the web
from your favorite web browser contained in your linux distribution.
4th Step : Troubleshooting
If you have any troubles in configuration or in using UbuDSL, first, have a look at the FAQs below
1.Modem is synchronizing but there is no connection.
In
this case you have to try to unplug the modem, wait a few seconds, plug
the modem in and wait to modem synchronize. Then try to connect. If it
still doesn’t work, please generate log and send it at
ubudsl(at)gmail(dot)com with problem description.
2. Modem is synchronizied,connection is established but I can’t browse websites.
a) Probably this is a fault of the DNS servers. Try to use OpenDNS servers. for that perform these commands
sudo rm -rf /etc/resolv.conf
sudo /opt/ubudsl/ubudsl --set-opendns
b)
If you use Ubuntu and your browser is Firefox, the web browser may be
run in the offline mode. To switch to the online mode, simply uncheck
the Work Offline position in the File menu.