Abstract: A bi-directional system for interconnecting devices on an Internet Protocol (IP) network, such as the Internet, is described. The bi-directional system employs an identifier scheme, such as telephone numbers, to identify the devices. The devices are communications devices, such as, but are not limited to, a telephone, computer, laptop, personal digital assistant, cell phone, video camera, videoconferencing system, or smart phone. The devices are network enabled and may be endpoints in IP Private Branch Exchange (PBX) systems, respectively. The devices may be interconnected by the bi-directional system to exchange communications in a peer to peer fashion. One or more devices may include a service that interconnects with a public switched telephone network (PSTN) such as, but is not limited to, a conferencing server, a voicemail system, an answering service, a multipoint-video mixing system or a mobile phone service.