Liberty Global Inc.'s UPC Broadband has topped the one-million mark for cable telephone customers in its European footprint. UPC blazed the cable telephony trail with early circuit-switched deployments, while migrating to IP-based solutions using PacketCable NCS and Session Initiation Protocol (SIP). UPC says it has doubled its telephone customer base over the last 15 months on the heels of service rollouts in the Netherlands, Hungary, France and Switzerland, and recent VoIP deployments in Austria, Poland and Romania. Later this year, UPC says it will introduce VoIP service in the Czech and Slovak Republics and Ireland. Entering 2006, UPC Broadband passed 18 million homes in Europe, of which 9.3 million were marketable for telephony service. UPC Broadband's VoIP vendors include Nortel, Siemens, AudioCodes, ARRIS and Scientific-Atlanta. The MSO has broken with other cable operators by deploying SIP-based telephony immediately, rather than waiting for its integration with PacketCable. UPC says the decision puts them on a fast-track to offer presence-based services, multimedia instant messaging and video telephony, as well as converged mobile and fixed line services. Including its operations in Japan and Latin America, Liberty Global counts 2.3 million phone customers.