This device is an advanced hybrid communication system from Panasonic, model KX-TES824. Initial Capacity: The device comes with an initial capacity supporting 3 external lines and 8 internal extensions. Expandable: The system's capacity can be increased to a maximum of 8 external lines and 24 internal extensions by adding expansion cards. Key Features: Supports features such as Automatic Answering (DISA), system programming via USB port, and is suitable for homes and small to medium-sized businesses.