Private Automatic Branch Exchange (PABX) has powered corporate communication systems for many years. PABX consists of several components, such as stations and lines in a closed network. While businesses with a PABX can use a platform of their choice, their service provider must use a Public Switched Telephone Network.

Since voice communication is such a key part of corporate operations, some businesses have decided that every employee must have their own phone. If the business is using the traditional phone-line architecture, its phone bill will be quite high. A PABX system can lower the phone bill because many employees will be using the same phone line. Moreover, the employees will be able to make internal calls via short extension numbers. Ultimately, the introduction of a PABX system reduces the number of physical phones within the business premises.