I have a question about it, I have 45 extensions all set to pbx delivers audio I have always had it this way.(45 extensions in all 30 local, 14 sbc , 1 remote stun). I started this thread cause I asked in another thread the answers I got were below. My question what happens when you uncheck it? Checked I guess more stress on pbx, more load more traffic. No Pbx Delivers audio: So would the phone be connected right to the Voip provider rtp stream? After the Call is setup with the PBX? I can see where this would help with network traffic as it is pbx runs fine 8 2.4 ghz cpus 8gb ram for most part sits at 1-2% cpu and 2gb ram usage and network traffic like 3mb with 20 calls simultaneously.