The Poly VVX450 Business IP Phone delivers engaging communication experiences with a color display and 12-line keys. The phone is a higher-level endpoint option to support both your lines and autodial, also to provide you easy-to-find features like transfer and conference. The CIS Secure DTD-VVX450-XX is a modified version that connects to your network like any other Poly VVX450 phone. The difference is the addition of the positive Disconnect On-Hook Security which is controlled by the TSG button. The CIS Secure DTD-VVX450-XX supports Session Initiation Protocol (SIP), Session Description Protocol (SDP), IPv4, and IPv6. Compliant for use in SCIF and SAPF environments, the phone also allows the On-Hook security features to be engaged while in a call providing enhanced “Hold” and “Mute” security. The additional features of the DTD-VVX450-XX include removable microphone and enable speakerphone protected by the TSG On-Hook security.