The telephone exchange is the name given to the telecommunication system that has been developed to ensure the continuity of communication between many telephones, generally connected to a center, and that automatically directs incoming and outgoing calls.

The switchboards, which constitute the most important part of telephone communication, were operated manually (manually) when they were first produced. The person who wanted to make a call first connected to the operator and said the number he wanted to call. The operator was also making the connection between the caller and the called person manually. Instead of these first manual exchanges, automatic telephone exchanges that perform line routing are used today.

Today, telephone exchanges are generally used for intra-company communication. Within the company, the telephones connected to the exchange can provide free communication between them with internal numbers (telephone codes) and can easily make calls with external lines.