So-called system phones are often used in telecommunications installations that have PBXs (private branch exchanges). These are specially designed for use with the respective phone system and make specific functions of the system easily and quickly accessible. Depending on the application, system phones are available with various designs and functions. They range from simple models for simple telephony functions, to system telephones with many features designed for specific employee roles or those with accessibility requirements, for example.
System telephones are often configured directly within the phone system. When an additional phone device is connected on another extension, the telephone system transmits the specific configuration to that particular phone. They can enable, for example, button assignments to be changed directly from the central telecommunications system. This makes it quicker and easier for large companies to effectively manage large numbers of telephone terminals.
Although the functionality of system telephones can vary greatly depending on the model and the type of PBX telephone system being used, certain basic functions are almost always available. For example, there are usually separate functions for internal and external forwarding, switching voicemail on and off, call waiting, initiating conference calls, the activation of on-hold music and a mute option. In addition to system phones, which are connected by cable to the phone system, there are now cordless systems available. They communicate with the PBX by DECT or via WiFi.