Interesting questions. Firstly, I do not believe that anyone has developed a software only detection for answer machines etc and hence I would expect that voice cards such as Dialogic are still required. If this is true then I would expect the cards to be connecting back to a traditional PBX on line side or possibly the VoIP Gateway/Router if using a trunk side card.
This certainly looks like the configurations for other IPCC suites (eg. CISCO) however we’ve not actually tried it yet but when it comes to IP Telephony we will still have a PBX on the network and hence thats what we’ll probably use to connect the dialer.