The Siemens optiPoint 420 familyAll telephones in the Siemens optiPoint 420 family are equipped for VoIP telephony with standard voice codecs and QoS mechanisms. High voice quality on the telephone is provided by using the G.722 (wideband) voice codec. Power can be supplied either locally or via Power over Ethernet (PoE) in accordance with the IEEE 802.3af standard. Open hardware and software platforms enable future capabilities and features such as the SIP VoIP protocol. All models support Computer Telephony Integration (CTI).The Siemens optiPoint 420 advance model is particularly prestigious: 18 function and 3 dialog keys, full duplex hands-free operation and the large-format, four-line graphical display offers maximum convenience when telephoning. In addition, optiPoint 420 advance supports standardized SIP features and is rounded off by the option of two slide-in units for expansion with add-on modules and application support via the optiPoint application module. This telephone is particularly suitable for use in management offices, conference rooms and luxury hotel rooms.