Packet network telephone interface system for POTS

This invention relates generally to communication systems, and more particularly, to a device for communicating voice data over a packet-based data network. The packet network phone unit is an interface between a telephone instrument and a packet network for enabling voice data to be communicated over the packet network. The unit also functions as a gateway between a packet network and a public switched telephone network, thereby interconnecting the networks and providing a public switched telephone network gateway to a packet network. When power is not supplied to the unit, a fallback switch automatically links the telephone instrument directly to the public switched network, bypassing the circuitry in the unit. The unit includes links to a plurality of external serial communications lines as well as an interface for connecting to a personal computer. The unit also includes an LCD driver and a display for displaying information such as a caller identification. The packet network phone unit also may function an answering machine/messaging system.