tcleim

Hi everyone I was recently hired and the company I work for utilize this software and nobody knows how to configure it. I already have a SIP account and I have already installed Express Talk in all computers. However, when I try to make a phone call, I can't hear a sound. I figured that I have to open up some ports and I've done so. I've already opened ports 8000 and 5070(default ports). What else am I missing? Thanks in advance.