Hosted PBX based on Voice over IP (VoIP) is the evolution of business telephony services. Instead of you operating a PBX on your premises it is operated by a provider in their data center(s).
The major benefits of a Hosted PBX are:
A professional Data Center is much more secure than your office
Hosted PBX services run on enterprise grade servers designed to operate under heavy load and are much more reliable than equipment running locally in your office
Quality Hosted PBX providers operate redundant data centers to ensure no downtime in the case of any outage. This gives you an additional element of safety.
Hosted PBX operates over internet connections, therefore, you can access your telephony services from anywhere in the world as long as you have a reliable internet connection.
Most Hosted PBX services offer the option to use mobile phones as end-points on your business phone system. You can, therefore, access your business telephony services when you are on the road and not be tied to your office phone.
Hosted PBX services are sold by the user (or seat). You, therefore, only pay for the number of users you need and do not have to purchase more capacity than you need. You can also increase and decrease the number of users based on the needs of your business.