Thursday, December 20, 2007

For a seasonal offer Sri Lanka Telecom (SLT) is given away free ADSL USB Modem ZTE ZXDSL 852 for customers who byuing ADSL Connections. This package contains ZTE ZXDSL 852 (SGS Thomson Microelectronic chipset) ADSL USB Modem, Driver CD for Window and ADSL Splitter. But there are no drivers for Linux. This simple guide will help you to install this modem in Ubuntu Gutsy (I believe this will also work with Feisty).

First you have to download this nice piece of Software from
You can download UbuDSL 0.5(i386) from here.
You can download UbuDSL o.5(amd64/Ubuntu 7.10 only) from here.

You can install the package using follwing commands:

sudo dpkg -i ubudsl_0.5-1_i386.deb

After successfully installing the package, you have to configure the connection. Before condigure the connection you must have Ubuntu Installation CD with you.
To configure the UbuDSL goto Applications->Internet->UbuDSL - configuration.
Then you will get a window like following.Click Next button and select your country from the list and enter your username and password and click start.
Then it will display the following screen and ask for the Ubuntu Installation disk .
After finishing the configuration process it will display the following window.
Then press quit. Before you reboot SLT customers have some thing to do.
Use following command open the options file in /etc/modprobe.d/

gksudo gedit /etc/modprobe.d/options

Find a line that starts from "options unicorn_usb_eth" and replace in this line PROTOCOL=pppoatm ENCAPS=vc-encaps by PROTOCOL=pppoe ENCAPS=llc-encaps. Save the file, quit the editor and reboot your computer.

After rebooting your connection will appear on your gnome panel, and display connected message. If you doesn't enable autostart option, you have to manually open the UbuDSL - connection monitor and press connect button. Connection monitor can found in the Applications->internet menu.

Special thanks goes to
Adrian Łubik who is the founder and programmer of this tool.


janaka said...

Thanks for the nice post!

I followed the sequence and got the modem to work. It gets connected and I get the IP as well.

But I cannot browse with fire fox or acess internet. Any ideas why?

adrian5632 said...

So probably you have to set another DNS servers. Try the OpenDNS - here you have simple guide how to change the DNS servers

janaka said...


janaka said...


Dushan said...

Can someone kindly help me with this :

I installed the ZTE DSL 852 modem and got it to work..but after I reboot the system , the 'LINK' indicator on the modem keeps on blinking and when I try to connect the following error msg appears "Cannot connect,Hardware Error"

But after sometime i was able to connect again.Any idea about this error msg..??

Anusha said...

Does this piece of crap work with Vista? :P

pathum said...

Guys I've been using Dialup on my rig with Ubuntu...Got ADSL recently but still am stuck in 1 place.... if anyone has had success with putting together Gutsy n the new SLT ADSL modem n surfing then pls pls tell me how...MAIL ME on
Tnks n Rgds

adrian5632 said...

@dushan: give us the output of the dmesg|grep unicorn command when you get this message.

Buddhika said...

I am a new comer to ubuntu/linux. i tried that above mentioned way to install my ZTE ZXDSL modem (from SLT) on Ubuntu 7.1 Gutsey, but there are problems.
For you to get a better idea of this matter i tried to be informative as i can.

One is Modem does not seems to be "ON" in anytime (pwp bulb and all other bulbs are off even when it 'try'to connect)

Also after giving username and password stuff to the ubuDSL configuration program , it gets to the point where it says installing development packages, and suddenly stops responding.
then if i force quit and try to do the configuration again it WORKS! it asks me to rboot, then i change that "options unicorn_usb_eth" thing and reboot.(it also dont ask for the Ubuntu cd)

But it work, in the connection monitor it dont connect even i use connect button to establish a connection.

I get the feeling modem doesnt get power thru usb, but if i unplug the modem and try to connect it says "no Modem", so it has identified the modem no?

Also in the hardware information under the ADSL Modem Advance tab;
it states ; usb.is_self_powered bool false

although i tried to edit that 'false' to 'true', it cannot be changed.

Any help or any of ur advice is highly regarded.


Anonymous said...

I got this modem and its work fine with my windows xp.In the license agreement they(slt) gave it said that this modem is not working with windows vista. And it is true.Is there any computer Wizard who know to fixed this Please leave a comment.

Ishan said...

This is not directly related to this post. But it may help some one.

I installed the modem driver and set up it with XP. The line connects only when I dial a number thru the phone. Till then modem finds it difficult to pick the ADSL connection

janaka said...

To solve problems use a newer version of UbuDSL. You can download it from

It should work.

These instructions are also useful

But use net to download newer version

Forrest said...

Milinda, A bit off topic but I'd like to make a suggestion that will make taking screen shots a lot easier. It looks like when you take a screen shot for a particular window you take one of the whole screen and then crop it. You can easily take one of just the active window using Alt + PrintScreen instead or just PrintScreen. That doesn't currently work as well if you have Compiz running though as the window border isn't captured. Otherwise it can save a lot of hassle.

Milinda Lakmal Pathirage said...

Thanks forrest for the tip.

Asiri Indush said...

Hi Milinda,
I have the same issue Buddhika is having. Everything was done as of your guidelines, But the modem does not get power. Lights are never blinking. Do you have any suggestions for that?


Anonymous said...

Great blog with lots of useful information and excellent commentary! Thanks for sharing. DSL high speed internet access

Harindu said...


can u help me up with my zte 852 dsl on Linux Mint 5....!

i tried installing ubudsl but it's not working...


~LAS~ said...

Thanx a lot man..Iv been trying to get my conextant access runner up for like two yrs..Finally this helped..

waruna said...

I tried to make the modem work in Ubuntu 8.10, according the instructions in UbuDSL site (
The link LED is keep on lightin'
But when I try to connect it gives the following error
"Can not establish connection. PPP daemon's message:
Timeout waiting PADO packets"

Pls help me to solve this problem

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