If any company is seeking to establish their place in the PBX replacement market using VoIP it has to be Covad with their announcement today of number of markets sold.
The product they are offering is a result of their acquisition of GoBeam. Given their business penetration with DSL this is looking more and more like a good move for Covad. Whose getting left behind? CallTower was first to make big noise in this space and needs to engage in more marketing. With so many Cisco installations around the USA, the CallTower product is very reliable and is proven. Then there is Packet8. They too want to play in this space as does GloPhone, but for now Covad is showing its teeth and flexing its muscles.