The Model 5800 is a Voice over IP Telephone Adapter, which allows standard analog telephones to make and receive calls over a cable or ADSL Internet connection. A conventional phone or cordless phone is plugged into the adapter and then the adapter is plugged into a broadband connected router or Internet gateway. A minimum of five attached phones can be rung simultaneously using the built-in ring generator. The model supports industry-standard Session Initiation Protocol (SIPv2) and works with a wide range of service providers and SIP-based VoIP equipment. The Model 5800 also supports G.711, iLBC and G.729 Codecs.