Hosted VoIP is a form of business VoIP (see VoIP) services where the VoIP equipment, servers and services are hosted by the VoIP provider. The provider manages calls and routes them to and from the subscriber’s existing telephony system and equipment. Hosted VoIP is also frequently referred to as managed VoIP. A hosted solution can save companies from the potentially expensive costs of having to invest in VoIP equipment and manage the system themselves. Hosted VoIP services use packet-switched telephony to transmit calls over the Internet as opposed to the circuit-switched telephony used by the traditional Public Switched Telephone Network (PSTN). In some hosted VoIP cases calls from the subscriber are routed over the PSTN to the hosted VoIP PBX system.