I tracked down the problem with crashes at startup (and with no window appearing). I was trying to make the last column of the call list as wide as possible when resizing the window. With some display settings, the reported width of the client window is off by 1 pixel. Instead of automagically adding a scrollbar, wxWindows starts running around in circles. Sooner or later (sometimes much later) it crashes. I've left a couple of pixels' buffer, and redone the dialling logic. The most frequent critique I've gottn is that it is cumbersome to require server configuration to dial a number. Now you don't. If the dialstring in the text box contains a username, hostname and extension, then it is dialled as-is. If there's a hostname and extension, we try to lookup username and password from a registered server with that name. If there's no server in our config with that name, dial it as-is (assume no username needed) If there's just an extension, then use the default server that you've (hopefully) configured. Windows : http://iaxclient.sourceforge.net/iaxcomm/iaxcomm-win-current.zip Linux: http://iaxclient.sourceforge.net/iaxcomm/iaxcomm-lin-current.tar.gz Next features to add are optional autoanswer for intercom functionality and streamlining the phonebook (only storing dialstrings)