Key extension for the Auerswald COMfortel 3500, 3200 and 2600 with 30 Tasten.Wird COMfortel fed 3500 with PoE (Power over Ethernet), then connect the first Beistellmoduls COMfortel Xtension300 is to be ordered separately power supply (COMfortel XT-PS) are required. This power supply supplies so all other additional modules. Supplied If the COMfortel 3500 via the included AC adapter to power, then to additional power supply (COMfortel XT-PS) is required to connect the second key extension.