SMC Networks SMC7004ABR V.2 - Manual (Page 6)

About the Barricade™ Router
2
This disconnect only happens if there are no more open requests
received from either the LAN or the WAN side (here this can be
requests from the internet, i.e. initiated through the use of so
called file sharing programs like eMule, eDonkey, etc.) that keep
the router active.
In order to counter such incalculable activity and protect yourself
from higher than expected on-line costs we therefore recommend
again a flat-rate contract for your DSL-connection.
The only safe alternative: Pull the plug!
That is to disconnect your router from the mains.
Please feel free to contact our SMC-hotline if you have further
questions.
** Flat-rate is an offer of your DSL-line provider, which gives you
timely unlimited access to the Internet at a defined (flat-) rate.