Itching to know the difference between a hosted VoIP phone system and a hosted PBX phone system?!
Well wait no further! Essentially...
There is no difference!
Technically: The signaling is done with an IP phone to the IP-PBX server using a LAN. Calls can go through a traditional phone company as well as voice over Internet (VoIP) using SIP trunking. Gateway cards are used to connect the system to the traditional phone company provider. (Jun 3, 2016 Hosted PBX Vs On Premise PBX - voip-info.org)