The function allows you choosing a number that you want in order to
light up during the call to traditional telephones. You can also unlist the
number and it won’t light up.
Shared Extension is when a group of agents has one and the same extension line. During the incoming call the phone will ring at several agents simultaneously.
Mirrored Extensions is when you have one and the same extension line on several phones, in example, in the office, at home and on the cell phone. So when someone calls your extension all you phone sets sharing the same extension will ring.