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 g722 wideband voice codec power can be supplied either locally or via power over ethernet poe in accordance with the ieee 8023af standard open hardware and software platforms enable future capabilities and features such as the sip voip protocol all models support comp