rcireland,
Not a problem, those are standard industry terms for the buttons that light up on your phone.
Direct Station Select [DSS], Busy Lamp Field [BLF], Programmable Key Module [PKM].
Basically, you are trying to show each station on a button below the display to determine whether it is Busy or Available via the light; BLF. It will also allow you to transfer calls directly to that station just by pressing their button; DSS.
Thanks,
TE