Editing Centrex (section)

==Phasing out==
In the United States, the usage of Centrex lines has fallen from 16.5 million in 2002 to 10.7 million in 2008 as users transition to IP-PBX (through VoIP).<ref name=Reed1>{{cite journal|last=Reed |first=Brad |title=Centrex: It's alive (for now)! |journal=Network World |date=February 13, 2012 |volume=29 |issue=3 |pages=10 |url=http://www.networkworld.com/news/2012/020712-centrex-255808.html |access-date=22 February 2012 |url-status=dead |archive-url=https://web.archive.org/web/20130703141234/http://www.networkworld.com/news/2012/020712-centrex-255808.html |archive-date=3 July 2013 }}</ref><ref name=ict1>{{cite web|title=TIA'S 2009 ICT MARKET REVIEW AND FORECAST|url=http://www.tiaonline.org/images/mrf/Chapter3_2009MRF_preview.pdf|publisher=The Telecommunications Industry Association|pages=3–20|year=2009|access-date=2012-02-22|archive-url=https://web.archive.org/web/20180521171336/http://www.tiaonline.org/images/mrf/Chapter3_2009MRF_preview.pdf|archive-date=2018-05-21|url-status=dead}}</ref> Centrex continues to be used by large institutions, government agencies, and universities as most of the equipment has already been paid for, though leasing Centrex lines may be more expensive.