I don't know when, but all of the sudden, my intercom button does not work. I have tried switching it with inactive phones in our office, but that doesn't work. When I switched the phones, the intercom button worked for the other phone line and the intercom button on my line still did not. This is not a troubleshoot item and I'm at my limit!

You have 24 flexible buttons. Your Intercom should have been on the 24th button- bottom right hand corner if default. Press the 12th button (second row from top- last button) and see if the intercom is not there now.

Use intercom **3 to move it back. If that doesn't work what is the KSU your using?