I have read the I1230 I.P. user guide and I see where there are 10 line/feature buttons. It refers to having "10 keys for user defined key labels" and "10 line/features you can access through 2nd page functionality". Does this phone use a shift key for accessing the second series of buttons and does this mean I could have 2 intercoms and 18 other buttons for lines, features or autodials?