Utilising your data connection you can access voice services either as user based or line based systems.
Vonex ONdesk is a fully featured cloud phone system. No need to pay for maintaining an on premise system! You can use a physical handset or just use the softphone and mobile app which means you can work from anywhere.
Vonex Lineshare is for businesses that don't make many outgoing calls and just need to receive calls via a local number for business continuity. You chose how many lines you require.
You get the same functionality as a cloud PBX but only pay for how many lines you use.