The IP Office platform comprises 4 models: IP Office - Small Office Edition, IP406, IP412, and IP Office 500 system. The IP406, IP412, and IP Office 500
(IP500) systems can have expansion modules added to them to match the requirements of a growing business.
Avaya IP Office delivers full voice functionality with a comprehensive set of features. The system can be configured as a voice-only PBX using traditional
circuit-switched lines or as an IP telephony server using high-speed ISDN/PRI dial-up access and/or direct leased line connectivity and/or SIP trunks.
The IP Office - Small Office Edition supports a maximum of 28 telephones; the IP406 supports a maximum of 190 telephones; the IP412 supports a maximum of
360 telephones; the IP Office 500 system supports 270 telephones