Hi, I originally started with two lines, and had entered in #104=2. The manual warns against using #104 later when adding lines. I have now added a third line, and I just cannot figure out how to get the third line button (third from left in row above Intercom buttons) to respond and behave like it is associated with the third trunk line. I am thinking I may have to use #104=3 and then just re-configure the fields that the manual says will be overwritten by changing #104 midstream. Can anyone help? Thanks.