Wobbles

Can anyone shed some light on this one - I've been experiementing with the trial version of IVM and it works fine with internal calls, but the moment an external call is directed to the extension the IVM is connected to I have problems. The specific problem with external calls is that the line is answered after just two rings with tones, IVM does not seem to detect the call at all. - The Hybrex BX-8 PBX uses two different ring cadences to indicate internal/external calls. - I've tried Win 98SE and XP Pro - Pragmatic modems with PCTEL and Motorola chipsets, and a Genius PCI-L Modem The only common factor that I can see, is the PBX and the actual PC. I started this project quite some time ago and ended up putting it on the back burner due to the lack of progress and other more pressing projects, but now that I've got a moment I'd quite like to solve the issue or at least establish where the problem lies.