Definition of centrex in US English:


(also Centrex)


  • A telephone service in which a group of phone lines can be joined by part of the local exchange acting as a private exchange.

    • ‘Service may be provided by commercial analog lines or via centrex (central Office exchange service, provided by a switch managed at the provider's central Office).’
    • ‘Hosted IP Centrex is designed for customers that want all the features of a PBX or Key system without the associated capital, lease, or maintenance costs.’
    • ‘IP Centrex and Hosted PBX services provide a valuable potential source of new revenue for service providers.’


1990s: blend of central and exchange.