Fix README for variables (bug #3209)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@4703 65c4cc65-6c06-0410-ace0-fbb531ad65f3

doc/README.variables

@@ -80,8 +80,8 @@ The dial() application sets the following variables:
 
 ${DIALEDPEERNAME} Dialed peer name
 ${DIALEDPEERNUMBER} Dialed peer number
-${DIALEDTIME}   Time for the call (seconds)
-${ANSWEREDTIME} Time from dial to answer (seconds)
+${DIALEDTIME}   Total time for the call in seconds (Network time).
+${ANSWEREDTIME} Time from answer to end of call in seconds (Billable time).
 ${DIALSTATUS}   Status of the call, one of:
                 CHANUNAVAIL | CONGESTION | BUSY | NOANSWER | ANSWER | CANCEL