There are several Wi-Fi enabled mobile phones that have pre-installed SIP client software, or are capable of running IP telephony clients, including most smartphones.
Analog telephone adapters provide an interface for traditional analog telephones to a voice-over-IP network. They connect to the Internet or local area network using an Ethernet port and have jacks that provide a standard RJ11interface for an analog local loop.
A VoIP phone or IP phone uses voice over IP technologies for placing and transmitting telephone calls over an IP network, such as the Internet as provided by Luli Fiber, instead of the traditional public switched telephone network (PSTN).
Digital IP-based telephone service uses control protocols such as the Session Initiation Protocol (SIP), Skinny Client Control Protocol (SCCP) or various other proprietary protocols.