In the present scenario when Telephony systems are moving to a common wiring plant the end station of a LAN or IP- based PBX must be simple to use, familiar and relatively cheap. While the H.323 recommendations are pretty expensive, an H.323 proxy can be used to communicate with the Skinny Client using the SCCP.[para] Here the telephone is a skinny client over IP, in the context of H.323. A proxy is used for the H.225 and H.245 signaling. Skinny messages are carried above TCP and use the port 2000 at the same time the skinny client (i.e. an Ethernet Phone) uses TCP/IP to transmit and receive calls and RTP/UDP/IP to/from a Skinny Client or H.323 terminal for audio.