Just like our Outdoor Intercom, the CyberData Indoor VoIP Door Entry Intercom is a Power over Ethernet (PoE 802.3af) and VoIP (Voice over IP) two-way communication and door entry device. The Intercom easily connects into existing local area networks with a single cable connection and is compatible with most SIP-based IP PBX servers that comply with RFC 3261. The Intercom is compatible with most SIP-based IP PBX servers that comply with the SIP RFC. The VoIP Intercom can be configured as a Night Ringer with two SIP extensions. One extension can be assigned to a page group for auto answer paging. The second extension can be assigned to a “First-to-Answer” Night Ring group with IP phones. An audio ring file is activated when the second SIP extension of the Intercom is dialed. If any of the IP phones in the ring group is answered (or if the caller hangs up), the Intercom stops ringing.