ISP Internal Doco

I work in a 2 bit ISP, I am trying to create screenshots/simulators of how the ADSL modems work. I have had limited success using screen dumps and exporting the html using FlashGet, or utilising sites such as screenshots.modemhelp.net.

I am looking for more and better ways to create these (where you load a normal html page and it looks like an ADSL modem)