Hi,
Functionality wise , using -d or not, or -X 15 or not is the same. You can do the capture in another way, add the options in the init script /etc/rc.d/init.d/fop2, something like
OPTIONS="-d -X 1 -l /tmp"
Then restart fop2 via init script, it will go to the background (-d) and also log output to /tmp/output.log
From what I have seen, ghost calls happens when doing broken attendant native sip transfers with some phones.