The EPABX may be defined as a switching system that makes available both internal and external stitching functions of any organisation.The selection of an EPBAX is a difficult task and requires deep knowledge of traffic pattern of the office. By using an EPABX both the internal and external needs of the organisation are fully served. With the advent of powerful microprocessors and advancements in the field of computers, the EPBAX can boast of versatile features. Hotline can be established between the boss and his immediate subordinates.EPABX has proven to be of immense use in communicating within office, making routine work simpler. It can be defined as a switching system for calls that enables both internal as well as external switching functions in an organization. Typically up to 10,000 subscribers can be accommodated by a single EPABX system.