asterisk users - Apr 2005 - Internet Conection Broken and asterisk can not route any calls

Hello all,

Sometimes my ADSL internet conection, gets down and I cannot access to internet.
When this happens, my asterisk gets crazy and it cannot route my calls.
Actualy I have an scape secuence (111) followed with the PSTN number,
and the call is routed trought my ISDN lines.
When my ADSL gets down, I cannot make any calls. If I dial 0 followed
the PSTN number I will use an VoIP provider trought Internet. I know
that if there is no internet I can not make VoIP calls, but why I can
not make ISDN either?

Any clue will be welcomed.

Thanks,

Ismael.