A PBX (Private Branch Exchange) phone system is a telecommunication system used within an organization to efficiently manage incoming and outgoing phone calls. It acts as a central hub that connects internal extensions with external lines and routes calls to the appropriate destination within the organization. PBX systems often include features such as voicemail, automated attendants, call forwarding, and conference calling, among others. They provide businesses with flexibility, scalability, and cost savings compared to traditional phone systems.