asterisk users - Feb 2006 - TDM 400 FXO FXS Test

Hi

Is there a test that you can do to test your modules FXS FXO to see if they 
are blown
I have a TDM400 with 2 FXS (green) modules on the the first two ports and 2 
FXO (red) modules
on the last two ports, but I can't seem to assign a channel to them. Can any
one help me??

Thanx
Jaco