I’ve followed the installation process outlined in "Asterisk The Future of Telephony. I have the TDM400P with one FXS module. My configurations are straight from the book so I have a dial plan on extension 611 to Echo test. I get a dial tone and any extension I press other than 611 results in a busy signal. So far so good. If I press 611 I get an echo if I press a key but if I talk into the receiver nothing is echoed back. Now I’m expecting the sounds to come back to the phone receiver so I don’t have speakers connected to my computer (in fact, I have my sound card disabled). This is okay, isn’t it? Maybe this is a really stupid question but this should all work with sound enabled (or heard) on the computer, shouldn’t it?