I hooked up a door box (essentially a 2500 set)to a TIP/RING SL port on a Legend R3. I want this door box to dial an extension automatically when it goes off-hook. I couldn't find a hotline feature in the Feature Reference, but maybe there's a weird name for it? I looked at Automatic Line Selection and I thought of using it in conjunction with a spare CO line port and ARS, but what a pain!