... Line keys6 Navigation keys(Arrow button, OK button, C button)Volume adjust, Hands-free,Mute,Headset,Message, ... Prompt, Voice MessageBLF, BLAExpansion InterfaceEXT: ESM32 programmable Key module*USB portApplicationSupport PSTN and VoIPPublic phone directoryPrivate phone directory* ... DC12V/1A outputPoE (IEEE 802.af)SpecificationsStorage Temperature:0°C ~ 60°COperating Humidity:10% ~ 90%Size:254mm ...