Virtual PBX systems, cloud PBX systems or hosted PBX systems are business telephone systems that 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.
See Melrose Labs Voice Gateway/CloudPBX
Melrose Labs: Our mission is to deliver pivotal services in cloud communications across mobile, fixed-line and internet for enterprises of all sizes. Through these services, we help businesses and other organisations communicate better with their staff and customers, and by doing so increase their success.