[asterisk-users] Inbound Voice Quality - Speed Change

[Jim Duda]

Many times the "speed" of an inbound voice call changes.  It's similiar 
to playing a 33 LP at 45 speed.  Sometimes the voice becomes uneligible. 
  A "speed" change is the best way to describe it, seems like the voice 
packets are being played out too fast.

Can anyone explain what might cause this?  It doesn't always happen, and 
seem unpredictable.

Thanks,

Jim