Telesym's CEO argues that enterprises that employ voice over Wi-Fi can save by cutting back on cellular calls made on campus: His numbers look great in this story, however, he's missing some major expenses. Most observers agree that the voice over Wi-Fi system is going to require a lot of support by IT folks. Also, the network has to cover just about everywhere. Since current Wi-Fi networks don't, an enterprise would have to invest in building out the network. And finally, right now the technology isn't there yet--there aren't yet good mechanisms for quality of service and fast handoffs.