A Private Branch Exchange (PBX) is a business telephone system that handles inbound and outbound calls for an organization. It traditionally uses copper landlines but has evolved into hybrid and cloud-based systems utilizing Voice over Internet Protocol (VoIP). There are several types of PBX systems, including PABX, IP PBX, and hosted PBX. Each type offers unique benefits and drawbacks, such as increased flexibility, scalability, and reliability with IP PBX systems, while hosted PBX provides a cloud-based solution with minimal maintenance costs. Understanding the differences between these options is crucial for businesses to choose the best fit for their needs.