Business telephony
IP PBX
Acronym: IPBX
An IP PBX is a telephone exchange routing calls as packets over the organisation's computer network, instead of dedicated telephone circuits.
It performs the same function as a PABX on another technology, with handsets plugged into the network rather than a telephone socket. For an analogue fax machine the consequence is direct: without a gateway able to speak the fax-over-IP protocol, it ends up behind a conversion it was never designed for.