We have an IPO 500 running 4.07. I have successfully setup the Softphone Pro VOIP and can send/receive calls from inside and outside (via VPN) the LAN. However, when calling an internal extension from the Softphone while on on the LAN, I cannot hear the person I am calling but they can hear me. When I call the Softphone from an internal extension it works fine. When I call the extension frome the Softphone using a DID, it also works fine. I am using the G.729(a) 8K CS-ACELP codec and I also tried the G.711 ULAW 64K codec.