Mitel MiVoice Dialog 4420 IP Basic Phone
The 4420 IP has 12 function keys with integrated LED indicators. Seven of the function keys are programmable for speed dialing or service features supported by the telephony system.
The remaining keys are used for locally controlled feature keys; mute key for switching off the microphone and volume control. The phone supports programmable ring tones and has a monitor-speaker for ongoing call or call set-up.