I am having a problem interminttantly with VOIP calls that have been set up by my vendor that dial out of my BCM 400 3.7 system out through my Option 81C system over a PRI circuit to make LD calls. This is working good, but interminttantly we are having problem where the BCM side can here us but we can't here them? Any suggestions? Right now this isn't in production we are only having test calls come to me here at the Opt 81c SIDE.