Cisco Systems is acknowledged as an early developer and strong promoter of PoE technology, referring to it as Inline Power in documents dating back to the late 1990s. Other companies involved in IP telephony also were working on proprietary powering schemes in the 1990s.
In 2000, Cisco published a report describing how it converted its San Jose, Calif. campus to an IP telephony system. Cisco used its Architecture for Voice, Video, and Integrated Data (AVVID) technology to connect 20,000 desktop telephones, located in 55 buildings in a two-mile (3.2-km) radius. The AVVID system’s Ethernet and voice switching units provided 7.5 W of “Inline Power” to the desktop units over CAT3 cable. This was an early large-scale implementation, using a “pre-standard” proprietary scheme.
In 1999, an IEEE standards working group issued a Call for Interest, and work on a PoE standard was underway in 2000. Early applications included VoIP private-branch-exchange (PBX) telephone systems.
In the ensuing years, PoE technology progressed in the following key areas: