How does the hosted PBX work

This infographic sample illustrates the hosted PBX system operation. It was designed on the base of the Wikimedia Commons file: Hosted pbx.jpg. [commons.wikimedia.org/ wiki/ File:Hosted_ pbx.jpg]
This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license. [creativecommons.org/ licenses/ by-sa/ 3.0/ deed.en]
"Virtual PBX systems or hosted PBX systems deliver PBX functionality as a service, available over the public switched telephone network (PSTN) or the Internet. Hosted PBXs are typically provided by a telephone company or service provider, using equipment located in the premises of a telephone exchange or the provider's data center. This means the customer does not need to buy or install PBX equipment. Generally the service is provided by a lease agreement and the provider can, in some configurations, use the same switching equipment to service multiple hosted PBX customers." [Business telephone system. Wikipedia]
The infographic example "How does the hosted PBX work" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Audio, Video, Media solution from the Illustrations area of ConceptDraw Solution Park.