asterisk users - Dec 2003 - D-channel

Hi list,

	I have an asterisk box with a TE140P using two span's (ISDN PRI
euroisdn). 		
	Today, the box was running ok, but twice it's just stops to make calls
and the CLI got flooded with the message "D-channel on span 1 up" and
"D-channel on span 2 up".	
	So I stopped asterisk, unload the module, load the module, ant them
started asterisk again.  After this, asterisk ran ok.
	Could anyone give me a clue on where to look at to discover what
happened?

[ ]'s
Eduardo