What is a Private Branch Exchange (PBX)?

A private branch exchange (PBX) is a private phone network used within a company or organization. The primary function of a private branch exchange is to allow employees to connect with each other internally, as well as make and receive external phone calls. In addition, PBXs can also play a recorded greeting for inbound callers, queue callers until someone is available, forward and transfer calls, and enable conference calls.

Early versions of private branch exchanges used copper wires and analog technology, which had some limitations. Now, many PBXs use voice over IP (VoIP), which provides more flexibility. One of the advantages of VoIP is that now organizations can have their private branch exchange hosted in the cloud, rather than on premises. This can be a more cost-effective model for many businesses.

Private branch exchanges (PBXs) are sufficient for most businesses, but call centers need something more robust - automatic call distribution (ACD) systems. ACD systems can do everything PBXs do, and more. For example, they allow agents to take calls from multiple phone queues. Furthermore, many of today's ACD systems can route not just calls, but also contacts from digital channels such as chat, which is important given customers' omnichannel expectations.