PC-to-PC, PC-to-Phone, Device-to-Phone:

By using PCs, broadband IP phones, VOIP gateways as endpoints, not only users can call each other for free, but also be able to access any PSTN or cell phone in the world via carrier network. Service providers only need a billing system and a softphone in order to launch a telephony service. Hardwares used as endpoints are: headsets for PCs, broadband (RJ45) IP phones, VOIP gateways.

Phone-to-PC, Phone-to-Device, Phone-to-Phone:

1. With virtual PSTN numbers, provided by telecom carriers, users can own local PSTN numbers and receive calls from PCs or IP phones online. A call-forward function enables a virtual PSTN number to be received at any particular phone in the world. This roaming service can be applied either on PCs or on conventional phones chosen by users.

2. By using VOIP gateways and IVR billing systems, users can call in from landline phones or cell phones. After keying in PINs for authentications, callers can then either make long distance calls or call online PC users directly.