38102ccb_stems___Reviews_of_2015_s_Best__Benefit
[Feature] PBX [Function] The central component of every multi-line phone system, the PBX acts as the switchboard, transferring and routing calls. It’s also the component that lets users put callers on hold and have conference calls. It integrates most of the other features listed here. [Benefit] 
Provides commonly used functions that allow many phone extensions to share lines and work together as one system.
Small Business VoIP & Phone Systems - Reviews of 2015's Best
Benefit