My mother runs Ubuntu (Lucid) on her laptop and she needed to make her NZ Telecom USB modem work. Getting an XT USB Modem working in Ubuntu provided a great starting point but there were a few things I had to do differently. I recommend printing the Rob the Geek article and then following this post for extra guidance.

The key issue is:

[these particular devices] respond to the system by default as a CD drive or USB hub so Ubuntu (with the stick in it’s native form) doesn’t see it as a modem device.
Getting an XT USB Modem working in Ubuntu

Fortunately, I had the option of dual booting into Windows XP so I could modify the modem (thus enabling Ubuntu to detect it as such). The missing step in the documentation for me was that I needed to install the modem under Windows first before I could see it in the Device Manager. In Windows XP, it was Control Panel>Classic View>System>Hardware Device Manager. I discovered the relevant port in my mother’s case was COM5. Yours may be different.

I used Hyperterminal for the next step. It wasn’t exactly intuitive to me but I got it to work. My main problem was I couldn’t see the interface responding as I typed in the command – at least not until it was entered. The command IIRC was AT+ZCDRUN=8

I received:

>> Close autorun
state result (0: FAIL 1: SUCCESS): 1
>> OK

I could then reboot into Ubuntu. The Ubuntu steps (look at Rob the Geek’s instructions) “Just Worked” and the modem just works. I was also successful getting another Telecom XT mobile going for my father-in-law on his eeebuntu netbook. So this was not a fluke.

In conclusion, there was only one small thing stopping everything else from working. Once fixed – complete success and an easy and intuitive user interface.