After experimenting with Skype as an audio bearer I noticed that Skype's echo cancelling algorithm distorted reception by reducing audio gain in the opposite branches in case of voice detection. It really destroys remote CW experience. I think this is something which was added to Skype lately.
The solution was found by installing IP-Sound, a freeware P2P bearer software developed by SM5VXC in Linkoping, Sweden.
It has multiple GSM and PCM codecs built in as well as a small TCP client with DNS support. Cool!
While googling for a freeware P2P application I came across a richly illustrated step-by-step IP-Sound setup guide. I forgot to tag it and since then I could not find it back. Here is my version:
1, Install the IP-Sound on both computers.
2, On the Server (the one connected to your radio), go to Properties and check "Auto-Answer" and uncheck "Restrict auto-answer to client list ip numbers" unless you have a private LAN and have static IP addresses for both PCs. Under "Sound" make sure you select the audio card that has the radio connected to.
3, On the Remote PC, press Client/Add and enter the Client Address window. You can add the addresses of the Server. Several addresses can be given here. DNS support is built in.
4, Open the selected port on the router. Be aware of bidirectionality in case of NAT, and make sure you let UDP through.
5, Connect