Selsius Systems was a telecommunications company in Dallas, Texas which developed and marketed some of the first IP telephony products in the industry.
It was acquired by Cisco Systems in 1998 and is the basis for the Cisco Unified Communications Manager (UC portfolio) today. Selsius designed an IP PBX system consisting of a line of IP phones, a server-based call control application – the Selsius-CallManager, a line of voice over IP gateways and voice applications including voicemail, an automated attendant console and a softphone.
Attached is a photo of one of the original Selsius IP phones (pre-Cisco acquisition). To this day a CUCM registered Cisco IP phone is identified (within CUCM) with the three letters “SEP” and its appended MAC address. The SEP stands for ‘Selsius Ethernet Phone”