[Asterisk-Users] What can cause a Red alarm?

[Matt Lawson]

I know having it unplugged from the line will cause this, but it's not. 
 It's an X101P single port FXO card.  Most of the time it works fine but 
occasionally "wigs out."  In this case zttool shows a red alarm.  Other 
times I call into it and it answers but I just hear a buzzing sound.  In 
a day or two I'll try it again and it'll be back to normal....

I have an el cheapo POTS phone right there to make sure the line is good.

There is a second, identical FXO card in the machine as well, which we 
haven't used in a long time.

Thoughts? (Besides swap the two cards and try the other one)