A little hard to explain. We have only one line going into the 4025. However, the unit "thinks" there are two lines. So we need to press one of the bottom right two keys to "select" an outgoing line, even though it is the same line. How do we tell the unit there is only one number coming into it so that when we pick up the handset we don't have to select a line? Thanks.

Lands Phones - Mitel - Superset 4025 Corded Phone (mitsup4025)