I want to change my work PC to Ubuntu but one thing is in my way... We use 12voip since we didn't find lower calling rates in Europe. The thing is 12voip doesn't have a Linux program :-(. I tried to set it up with instructions from this page (under 'Software configuration') with almost all clients that the software center of Ubuntu offers, but the best results i got to had a lot of echo. Now i must admit this echo exists also with the Windows version of the program, but there- once you use headphones its gone, while on the Ubuntu sip phones it stays and its worst in general. I don't know if my problem has to do with codecs or something else, and i was hoping someone can help check it and tell me which sip phone i can work with, and instructions on how to configure it correctly. Btw i tried Google, and all i could find were questions like mine or similar, no good answers.

Thanks!