Negatives

Although VoIP equipment costs less than PBXs:

the technology is new and thus upgrades are frequent (this takes time and effort)
PBXs generally last ~10 years and public exchanges ~30 years; while VoIP equipment is mostly computer equipment with a ~3 year amortization

Transcript

[slide63] However, there's some negatives. The first is, although the equipment costs a lot less than PBXs, the technology's rapidly adapting and therefore we may have to replace it sooner. And PBXs typically lasted 10 years, and public exchange is 30 years. Most voice over IP equipment has maybe a life of three years. So that's a problem. And from an environmental point of view, that's also bad, because we have to figure out what do we do to recycle all of these things.