A cloud PBX system is a based on cloud computing technology, where data is stored and transferred over the Internet, rather than on a computer or piece of hardware that an end-user owns. PBX, or public branch exchange, is the name used to refer to the technology that any given telephone provider uses to route calls. Originally, a PBX was a large unit of hardware that had to be stored on site and operated by hand.
The companies in this category offer PBX Software which mimicked the old systems and provide the same service for a fraction of the cost but which are much more reliable.
If you're looking for similar cloud software like PBX Software, consider our Cloud Contact Center Software and Call Center Software categories.