Avaya's IP Office is a modular communications solution that scales from 2 to 360 users. It provides a hybrid PBX with both TDM and IP phone support that can be used in either mode or both concurrently. IP Office has data capabilities built in, providing IP routing, switching and Firewall protection between LAN and WAN. IP Office has an integrated software applications suite that delivers a contact center, voice and email messaging, Interactive Voice Response, conferencing and computer telephony integration. IP Office solutions are built from hardware units and application software. Hardware provides the connectivity for voice and data circuits and processor units for the solution software. Each IP Office solution will require a system processor unit (Small Office Edition, IP406 and IP412), trunk connections to service provider, and expansion modules for TDM phone cabling. IP Phones connect over LAN connections to the IP Office solution.