Multi Tenant PBX - Which one to go for? What is a multi-tenant PBX?First of all it is worth just looking at what a multi-tenant pbx actually is? Simply put, it is a office telephone system that can be configured to operate a number of phone systems on the same system or hardware.It is great to serviced office centres or space that want to provide tenants with the option to rent or purchase office telephone system functionality from the building