3Com, a founding member of the SIP Forum, is the only major IP-PBX manufacturer that is making a big play with products based on SIP.
The 3Com VCX is a Convergence Applications Suite that uses SIP to manage call control, authentication, privacy, location and presence services. IP Telephony, a la, dialtone and those PBX-like features the IP-PBX market has been working for five years to perfect (message lamp, call forward, hold, call transfer), is one of a host of new applications enabled for enterprise communications.
These applications include centralized voice mail. Have you ever tried to compile and send a voice mail message to 100 employees scattered across 20 locations and 20 PBXes? – I thought about it when I was VP of Marketing at Nortel Networks. it's quite impractical with classic proprietary voicemail adjunct servers.
