You are designing the audio system for a restaurant. The restaurant owners plan to play background music in the dining room. They want to provide the restaurant staff with remote volume control — one control at the hostess station and one control located elsewhere in the dining room.
You would likely choose a DR1 as the remote volume control device (unless you also want to provide the user with a selection of background music channels, in which case you would probably choose a DR3 — but let's not get sidetracked. This is a Level control example!) You'll need two DR1 devices — one at the hostess station and one in a different location in the dining room.