Hi Alex. I know exactly what is happening with CQPhone because I wrote the program. It sends a tiny outbound UDP packet 3 times a minute to assist in router transversal. Many routers will create a 30 second inbound pinhole after experiencing an tiny outgoing packet to the same port and address. This is normal for CQPhone and it helps many people with router port forwarding problems. To send a tiny outbound UDP packet 3 times a minute is insignificant traffic even for a dialup connection.
This pinholing behavior uses only about 1/2000 of a typical dialup connection.
QsoNet uses a single, continuous, outbound TCP connection so there are no router issues at all.