You are best off doing wav (trust me) 
It can record at 8 16 22 and 32 khz if you can manage to have a channel at that speed.

syntax [record /tmp/blah.wav] 

dial * to end (dtmf only works in iax and portaudio {beg file to add it to mod_exosip})



git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@453 d0543943-73ff-0310-b7d9-9358b9ac24b2