What is destination channel hang?

Today in my CDR I see following entries. The destination says “hang” but there is a finite time spent on that call. Normally I see internal or external phone number in this place. Another one was just s. What are those destinations?

  1. 2009-10-01 13:39:01  	DAHDI/2-1...  	 hang  	ANSWERED  	02:31
  2. 2009-10-01 07:24:06  	DAHDI/2-1...  	 s  	ANSWERED  	00:56

Both calls were incoming calls from analog x100P clone card. I do not pay for caller id so that column is blank. The system seems to working fine but not sure about this.

I am running freepbx on elastix 1.5.2 distro. This data is from original freepbx cdr not from elastix modified freepbx screen. (Although freepbx shows the same).