AVR-Chat

>
>As for your problem, i don't know what SLIC means

Subscriber line interface circuit, which is not the right end.  The telco 
uses a SLIC to provide POTS to your instrument.

>but i know there are
>working circuits out there to detect ring and off hook, which can be built
>with discrete components and connected to IO pins of your Atmel. Google
>for "phone in use schematic" .
>You will then find plenty of stuff like this:
><http://www.ee.washington.edu/circuit_archive/circuits/F_ASCII_Schem_Tel.html>

Plenty of sort-of-working schematics there.

Check amazon and ebay for a book called "Understanding Telephone Electronics".
Google for "Part 68 approved interface".