URBESTCall Center Dialpad Headset Telephone with Tone Dial Key Pad & REDIAL FSK/DTMF caller ID display, automatic checking. As for the mute key, it goes like this. During the call, when you press "this key", the microphone will stop working,the indicator light will turn red. Press "this key " again, the call will function again. 30 incoming, 5 outgoing number memories. 2 digits PABX code setup, 32 digits pre-dial and edit. Package Included: 1 x Dial Pad,1 x Headset,1 x Connect cord,1 x English user manual. If you are looking for a fully functioning dialpad with headset to works with your call center affair, phone sales, telephone counseling services, insurance, hospitals, banks, telecom operators, enterprises, this one is the keeper.