Boss wanted me to check out this Yealink T28P. Provisioned fine.. reprovisioned by Cisco SPA-504G to a different extension. Took home, updated the host address and added the params for rport, STUN, etc.. reference http://www.3cx.com/blog/voip-howto/remote-extensions/ It worked fine to dial out to voicemail or to an external phone number.. audio is fine both ways. However.. when making an inbound call to it either from a local extension or from external, I get the ring and answer but the other end is still "on hold" waiting for me to answer. I'm behind a Linksys WRT54G on DD-WRT.. no SIP ALG or port forward in play. That was on Wednesday.. So.. I took that Cisco set home and configured the remote extension settings for the host, keep-alive, rport, NAT, and STUN.. worked like the champ which it is.. I've done remote extensions at home in the past on a few Cisco models. So.. I pulled the plug on that.. cleaned the bathroom and stuff (enough time for stuff to flush..) tried the Yealink.. same deal. Looks like it tries a couple of times if I hang up. I did try that ALLOWSOURCEASOUTBOUND to 1 param and reset the system.. put on a load of laundry to pass some time. Powered up the handset again.. still no go.. I'm hearing the old music from one end while apparently "answering" the call but not really. The PBX console agrees with my call.. the handset is apparently lost. Worse, I then notice that if I place the "call" on hold, the PBX begins placing an outbound call to the number I called from... Go figure. I'm going to throw a wireshark on there to see what the SIP traffic looks like, but it does seem that the acknowledgement from the handset is not being received at the PBX.. probably being sent on the wrong port.. or the SDP is wrong from the handset. While I can see that the PBX isn't getting the ACK.. it does appear to get the "hold" message being sent.. but must be wrong. Is there some other setting I'm missing for the Yealink? I did try a different local SIP port than from Wednesday.. I do see it registered at 5062.. Anything else?