https://www.cyberdata.net/
The CyberData SIP-enabled IP Outdoor Intercom/door Controller is a Power over Ethernet (PoE 802.3af) and VoIP (Voice over IP) two-way communication and door entry device with an integral 12-key backlit keypad.
The CyberData V3 VoIP Paging Server enables users through a single SIP phone extension, to access multiple zones for paging in a VoIP network and to connect to legacy analog overhead paging systems.