Also known asCloud Telephony, Hosted Telephony or IP Centrex, it is a VoIP solution that refers to a telephone installation(IPBX) hosted by the operator rather than the customer. This solution allows companies to outsource VoIP and free themselves from having to manage a PBX.

A company using a Centrex IP equips its site with a router connected to an xDSL connection and IP phones. Therefore, the local network must be compatible with IP telephony. An audit is preferable prior to the implementation of a Centrex.

In addition to the technological advantages, the Centrex IP allows a reduction in investments (more than PABX) and communication costs (no more distance-related costs, as most offers are flat-rate). In general, the Centrex allows a better control of its telephony. Previously reserved for large companies, the Centrex is now accessible to VSEs and SMEs.