The improvements in communications that come with the easier to use mixed applications of voice, video and data are what will make VoIP valuable. They are pushing the standards so one many vendors will make phones and will be able to buy such phones at say Frys. Tandy and Samsung have signed up to produce such standard phones. In the long run John Chambers has publicly stated he wants to get out of making phones. Catalysts will have 24 analog port blades for analog FAXes, modems etc.
Management expects to leverage investment in data infrastructure.
VoIP 1st step is to connect PBX to IP network to eliminate dependence on a carrier. Then connect IP phones to switches, and allow interfaces to PSTN but use IP as the driver. Can engineer the same level of reliability in data network as can in phone network. Thus the phone can be moved about. The GSM phone gateway is 802.11 but uses a different access point.