Customers are typically wrong about such things. At this point, if they really need to distinguish it from other calls, perhaps you could put some type of external ringer on for the door phone alert.
I cant understand what you are saying here:
"add F#7 plus 1-4 but all it does is say that it is distinctive ring but ring at all then"
Either way, F#7 is only for station level ringing, and does not effect individual CO lines on a system wide basis.
I know the manual mentions it, but the DHS-L is a discontinued model that was based on the DHS. The DHS had dist. ring at software level FP3. The mention of it in the L manual may have been a typo from the DHS manual. As I said above, if your system has the feature, it would be where I specified. Some versions of the L may have had it. Have you checked where I specified? (system programming/ co line config (line number)/ distinctive tone)
As for the system not impressing you, I feel the same way. In fact, I don’t even work on Vodavi anymore. I just answered your question because I figured nobody else would, as this forum does not get much activity compared to the others.