Misc. Dialplan Tools cng plc
From FreeSWITCH Wiki
cng plc is just an app that says to perform plc on any lost packets and execute on originate. It is like execute on answer, etc. but only for outbound calls during originate.
When experiencing an intermittent drop calls, it could be that the packets are probably late and being dropped and replaced with silence. You can try 2 things:
1) run the app cng_plc before bridge and in execute_on_originate on b legs.
2) enable the jitter buffer at a small value by setting jitterbuffer_msec=60
<action application="set" data="jitterbuffer_msec=60"/>