When there is no dial tone Internet still works?

No dial tone since morning but internet still works but speed drops from 490KB to 70KB

Some one told me 2-3 years ago that if there is current in one line internet will work. pata nahi sach hai yeah Jhoot

and SNR changes to 6 from 12.5 and Line attenuation 33-----47

Yeh internet works on dead lines, not a big deal.

different channels for voice and data transfer.