Thanks for the answer, it was a while back and maybe he meant the "ip on the fly", which I just heard about.
As to what I meant when I said 2 protocols at once, I mean SIP and whatever the native protocol is, about which I am clueless. By now you'll have figured out that I'm not a phone tech, but a router and networking guy. We're trying to get a remote phone working at one of my client's owner's house. I found out that he has an older phone at home and asked him to take a new one that supported IP to the house.
As I mentioned, he has an NBX 3000 running 6.0, and I understand that IP support is built into that rev of software. Although we can't use SIP because he still has a bunch of the old phones in the office where the switch is, we're going to utilize the IP functionality to make the phone at the house work.
Oh, maybe a bit of background would help. He has been running the old phone at his house for some time over a VPN through a Cisco ASA, and experienced a variety of problems, all of which have been resolved except for the occasional one way audio that occurs with some frequency. Current thinking is that this is caused by the router in the office, which is a Cisco without the K9 option, being overloaded trying to keep up with normal demand plus the decrypting chores that the K9 would offload were it there.
We're going to eliminate the asa and the VPN and just use straight IP with QoS to connect to the switch and see if that doesn't help.
Any ideas about resolving this, in case this doesn't work, would be very much appreciated.