Worldwide PBX/KTS revenue totaled $2.1 bln in Q3 2005, up 7% from Q2 2005, and 17% higher than Q3 2004, according to Infonetics Research. Quarterly revenue is forecast to increase 9% to $2.3 bln by Q3 2006, as the market continues to benefit from an improving economy and the overall move toward VoIP technology. IP PBX revenue jumped 10% between Q2 2005 and Q3 2005, reaching almost $1.7 bln. Hybrid PBXs made up most of the IP PBX growth this quarter, as pure IP revenue was up only 1%. The top PBX/KTS system vendors in Q3 2005 for total lines shipped are Nortel, Avaya, Siemens, Alcatel, and NEC.