I have a problem on isdn bri connection customer can't use the line sometimes. The only thing that I was able to detect is that the ISDN layer 2 goes down, deb isdn q921 show that). Is it possible understand if aslo Layer goes down ? It seem that layer1 still up (Show isdn status). From my experience I saw that puting out the cabling of a Bri that was working the layer2 goes down, but the layer 1 still up into the router. At the is it possible monitoring the layer1 in real time.