| 词条 | Centrex |
| 释义 |
Centrex service was first installed in the early 1960's in New York's financial district by New York Telelphone.[2][3] As of 2003, it was estimated that there were 20 million Centrex lines installed worldwide by 20 telephone companies, with the most installations in the United States (15 million), Canada (2 million), and Britain (1 million).[2] This accounted for approximately 5% of all installed business telephone lines, worldwide.[2] In terms of user-visible features, Centrex and PBX are similar. Features include:[4]
Phasing outIn the United States, the usage of Centrex lines has fallen over the past decade from 16.5 million in 2002 to 10.7 million in 2008 as users transition to IP-PBX (through VoIP).[5][6] 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.[5][7][8] References1. ^{{Cite book|url=https://books.google.com/books?id=yVMHAAAAQBAJ&pg=PA367&dq=centrex&hl=en&sa=X&ved=0ahUKEwiN75PPy9TfAhWvd98KHZGbCEA4KBDoAQhBMAU#v=onepage&q=centrex&f=false|title=Understanding Voice Over IP Technology|last=Wittenberg|first=Nicholas|date=2009-02-19|publisher=Cengage Learning|year=|isbn=9781111806613|location=|pages=367|language=en}} {{telecommunications}}2. ^1 2 {{Cite book|url=https://books.google.com/books?id=lcqPeexvyqkC&pg=PA2&dq=centrex&hl=en&sa=X&ved=0ahUKEwio3KaeyNTfAhWMTt8KHdJgDskQ6AEIKjAA#v=onepage&q=centrex&f=false|title=Centrex Or PBX: The Impact of IP|last=Abrahams|first=John R.|last2=Lollo|first2=Mauro|date=2003|publisher=Artech House|others=|year=|isbn=9781580536226|location=|pages=|at=Chapter 1, Introduction to Centrex|language=en}} 3. ^{{Cite web|url=https://themuseumoftelephony.wordpress.com/2016/07/09/telephony-101-centrex/|title=Telephony 101: Centrex|date=2016-07-09|website=The Museum of Telephony|language=en|access-date=2019-01-04}} 4. ^{{Cite book|url=https://books.google.com/books?id=vdbRmykbNZ4C&pg=PT143&dq=centrex&hl=en&sa=X&ved=0ahUKEwjjrOm_ydTfAhUrneAKHcYnAfsQ6AEIQzAF#v=onepage&q=centrex&f=false|title=Telecommunications and Data Communications Handbook|last=Horak|first=Ray|date=2012-11-19|publisher=John Wiley & Sons|year=|isbn=9781118585801|editor-mask=|location=|pages=|at=Section 3.3.1 (Features)|language=en}} 5. ^1 {{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 |accessdate=22 February 2012 |deadurl=yes |archiveurl=https://web.archive.org/web/20130703141234/http://www.networkworld.com/news/2012/020712-centrex-255808.html |archivedate=3 July 2013 }} 6. ^{{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}} 7. ^{{cite news|last=Hochmuth |first=Phil |title=VoIP converts say good riddance to Centrex |url=http://www.networkworld.com/news/2006/092006-interop-voip-centrex.html |accessdate=22 February 2012 |date=September 20, 2006 |deadurl=yes |archiveurl=https://web.archive.org/web/20060927210640/http://www.networkworld.com/news/2006/092006-interop-voip-centrex.html |archivedate=27 September 2006 }} 8. ^{{cite news|last=Greene |first=Tim |title=PBX v. Centrex |url=http://www.networkworld.com/news/2007/102607-arguments-pbx-centrex.html |accessdate=22 February 2012 |newspaper=Network World |date=October 26, 2007 |deadurl=yes |archiveurl=https://web.archive.org/web/20121023214711/http://www.networkworld.com/news/2007/102607-arguments-pbx-centrex.html |archivedate=23 October 2012 }} 2 : Telephone service enhanced features|Telephone exchanges |
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