Keeping DSL up and running

I use Kubuntu Dapper as my Linux Disto as it is the only one I have found that I can get DSL to even work. Now if only I could get it to stay up and running, it seems that after about 5 or 6 minutes of inactivity the connection goes down. Do not get me wrong I think that Dapper has to one of the best distos I have used. I just hope that somebody out there can help. I would use 5.10 but it will not connect to the internet at all.
I have a
Asrock SataII Mobo
512 Ram
160 gig Seagate Hd
30 gig WD
cdrw/dvd drive
dvd/rw/cd/rw drive
RealTek nic