A hosted VoIP system offers communications solutions using hardware located outside of your premises.
This means that a third party will cover the costs and management of building servers, hardware and software required to manage your connection. All your business needs is VoIP-enabled phones and a licence to get connected.
With non-hosted VoIP, your business would invest in servers and hardware located at your premises. You would be responsible for the maintenance and upkeep needed to keep your business connected.
This is an option that could suit large businesses with the space and budget to cover the costs of the investment.