The Siemens OptiPoint 500 Basic system phone has all the same features as the OptiPoint Entry telephone but is also has the adapter Interface. This allows the user to add the extra key modules that are available for the OptiPoint 500 range. The interface on the Siemens OptiPoint 500 Basic system phone will allow two extra devices to connect in total. This can be two extra key panels or a key panel and signature module.
